Data manipulation language (DML) statements in GoogleSQL

The BigQuery data manipulation language (DML) enables you to update, insert, and delete data from your BigQuery tables.

For information about how to use DML statements, see Transform data with data manipulation language and Update partitioned table data using DML.

On-demand query size calculation

If you use on-demand billing, BigQuery charges for data manipulation language (DML) statements based on the number of bytes processed by the statement.

For more information about cost estimation, see Estimate and control costs.

Non-partitioned tables

For non-partitioned tables, the number of bytes processed is calculated as follows:

  • q = The sum of bytes processed by the DML statement itself, including any columns referenced in tables scanned by the DML statement.
  • t = The size of the table being updated by the DML statement before any modifications are made.
DML statement Bytes processed
INSERT q
UPDATE q + t
DELETE q + t
MERGE If there are only INSERT clauses: q.
If there is an UPDATE or DELETE clause: q + t.

To preview how many bytes a statement processes, Check the estimated cost before running a query.

Partitioned tables

For partitioned tables, the number of bytes processed is calculated as follows:

  • q' = The sum of bytes processed by the DML statement itself, including any columns referenced in all partitions scanned by the DML statement.
  • t' = The total size of all partitions being updated by the DML statement before any modifications are made.
DML statement Bytes processed
INSERT q'
UPDATE q' + t'
DELETE q' + t'
MERGE If there are only INSERT clauses in the MERGE statement: q'.
If there is an UPDATE or DELETE clause in the MERGE statement: q' + t'.

To preview how many bytes a statement processes, Check the estimated cost before running a query.

INSERT statement

Use the INSERT statement when you want to add new rows to a table.

INSERT[INTO]target_name
[(column_1[,...,column_n])]
input
input::=
VALUES(expr_1[,...,expr_n])
[,...,(expr_k_1[,...,expr_k_n])]
|SELECT_QUERY
expr::=value_expression|DEFAULT

INSERT statements must comply with the following rules:

  • Column names are optional if the target table is not an ingestion-time partitioned table.
  • Duplicate names are not allowed in the list of target columns.
  • Values must be added in the same order as the specified columns.
  • The number of values added must match the number of specified columns.
  • Values must have a type that is compatible with the target column.
  • When the value expression is DEFAULT, the default value for the column is used. If the column has no default value, the value defaults to NULL.

Omitting column names

When the column names are omitted, all columns in the target table are included in ascending order based on their ordinal positions. If an omitted column has a default value, then that value is used. Otherwise, the column value is NULL. If the target table is an ingestion-time partitioned table, column names must be specified.

Value type compatibility

Values added with an INSERT statement must be compatible with the target column's type. A value's type is considered compatible with the target column's type if one of the following criteria are met:

  • The value type matches the column type exactly. For example, inserting a value of type INT64 in a column that also has a type of INT64.
  • The value type is one that can be implicitly coerced into another type.

INSERT examples

INSERT using explicit values

INSERTdataset.Inventory(product,quantity)
VALUES('top load washer',10),
('front load washer',20),
('dryer',30),
('refrigerator',10),
('microwave',20),
('dishwasher',30),
('oven',5)

+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 30 | NULL |
| dryer | 30 | NULL |
| front load washer | 20 | NULL |
| microwave | 20 | NULL |
| oven | 5 | NULL |
| refrigerator | 10 | NULL |
| top load washer | 10 | NULL |
+-------------------+----------+--------------------+

If you set a default value for a column, then you can use the DEFAULT keyword in place of a value to insert the default value:

ALTERTABLEdataset.NewArrivalsALTERCOLUMNquantitySETDEFAULT100;
INSERTdataset.NewArrivals(product,quantity,warehouse)
VALUES('top load washer',DEFAULT,'warehouse #1'),
('dryer',200,'warehouse #2'),
('oven',300,'warehouse #3');

+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 200 | warehouse #2 |
| oven | 300 | warehouse #3 |
| top load washer | 100 | warehouse #1 |
+-----------------+----------+--------------+

INSERT SELECT statement

INSERTdataset.Warehouse(warehouse,state)
SELECT*
FROMUNNEST([('warehouse #1','WA'),
('warehouse #2','CA'),
('warehouse #3','WA')])

+--------------+-------+
| warehouse | state |
+--------------+-------+
| warehouse #1 | WA |
| warehouse #2 | CA |
| warehouse #3 | WA |
+--------------+-------+

You can also use WITH when using INSERT SELECT. For example, you can rewrite the previous query using WITH:

INSERTdataset.Warehouse(warehouse,state)
WITHwAS(
SELECTARRAY<STRUCT<warehousestring,statestring>>
[('warehouse #1','WA'),
('warehouse #2','CA'),
('warehouse #3','WA')]col
)
SELECTwarehouse,stateFROMw,UNNEST(w.col)

The following example shows how to copy a table's contents into another table:

INSERTdataset.DetailedInventory(product,quantity,supply_constrained)
SELECTproduct,quantity,false
FROMdataset.Inventory

+----------------------+----------+--------------------+----------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+----------+----------------+
| dishwasher | 30 | false | [] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [] | NULL |
| microwave | 20 | false | [] | NULL |
| oven | 5 | false | [] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | false | [] | NULL |
+----------------------+----------+--------------------+----------+----------------+

INSERT VALUES with subquery

The following example shows how to insert a row into a table, where one of the values is computed using a subquery:

INSERTdataset.DetailedInventory(product,quantity)
VALUES('countertop microwave',
(SELECTquantityFROMdataset.DetailedInventory
WHEREproduct='microwave'))

+----------------------+----------+--------------------+----------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+----------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [] | NULL |
| microwave | 20 | false | [] | NULL |
| oven | 5 | false | [] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | false | [] | NULL |
+----------------------+----------+--------------------+----------+----------------+

INSERT without column names

INSERTdataset.WarehouseVALUES('warehouse #4','WA'),('warehouse #5','NY')

This is the Warehouse table before you run the query:

+--------------+-------+
| warehouse | state |
+--------------+-------+
| warehouse #1 | WA |
| warehouse #2 | CA |
| warehouse #3 | WA |
+--------------+-------+

This is the Warehouse table after you run the query:

+--------------+-------+
| warehouse | state |
+--------------+-------+
| warehouse #1 | WA |
| warehouse #2 | CA |
| warehouse #3 | WA |
| warehouse #4 | WA |
| warehouse #5 | NY |
+--------------+-------+

INSERT with STRUCT types

The following example shows how to insert a row into a table, where some of the fields are STRUCT types.

INSERTdataset.DetailedInventory
VALUES('top load washer',10,FALSE,[(CURRENT_DATE,"comment1")],("white","1 year",(30,40,28))),
('front load washer',20,FALSE,[(CURRENT_DATE,"comment1")],("beige","1 year",(35,45,30)))

Here is the DetailedInventory table after you run the query:

+-------------------+----------+--------------------+-------------------------------------------------+----------------------------------------------------------------------------------------------------+
| product | quantity | supply_constrained | comments | specifications |
+-------------------+----------+--------------------+-------------------------------------------------+----------------------------------------------------------------------------------------------------+
| front load washer | 20 | false | [{"created":"2021-02-09","comment":"comment1"}] | {"color":"beige","warranty":"1 year","dimensions":{"depth":"35.0","height":"45.0","width":"30.0"}} |
| top load washer | 10 | false | [{"created":"2021-02-09","comment":"comment1"}] | {"color":"white","warranty":"1 year","dimensions":{"depth":"30.0","height":"40.0","width":"28.0"}} |
+-------------------+----------+--------------------+-------------------------------------------------+----------------------------------------------------------------------------------------------------+

INSERT with ARRAY types

The following example show how to insert a row into a table, where one of the fields is an ARRAY type.

CREATETABLEIFNOTEXISTSdataset.table1(namesARRAY<STRING>);
INSERTINTOdataset.table1(names)
VALUES(["name1","name2"])

Here is the table after you run the query:

+-------------------+
|names|
+-------------------+
|["name1","name2"]|
+-------------------+

INSERT with RANGE types

The following example shows how to insert rows into a table, where the fields are RANGE type.

INSERTmydataset.my_range_table(emp_id,dept_id,duration)
VALUES(10,1000,RANGE<DATE>'[2010年01月10日, 2010年03月10日)'),
(10,2000,RANGE<DATE>'[2010年03月10日, 2010年07月15日)'),
(10,2000,RANGE<DATE>'[2010年06月15日, 2010年08月18日)'),
(20,2000,RANGE<DATE>'[2010年03月10日, 2010年07月20日)'),
(20,1000,RANGE<DATE>'[2020年05月10日, 2020年09月20日)');
SELECT*FROMmydataset.my_range_tableORDERBYemp_id;
/*--------+---------+--------------------------+
 | emp_id | dept_id | duration |
 +--------+---------+--------------------------+
 | 10 | 1000 | [2010年01月10日, 2010年03月10日) |
 | 10 | 2000 | [2010年03月10日, 2010年07月15日) |
 | 10 | 2000 | [2010年06月15日, 2010年08月18日) |
 | 20 | 2000 | [2010年03月10日, 2010年07月20日) |
 | 20 | 1000 | [2020年05月10日, 2020年09月20日) |
 +--------+---------+--------------------------*/

DELETE statement

Use the DELETE statement when you want to delete rows from a table.

DELETE[FROM]target_name[alias]
WHEREcondition

To delete all rows in a table, use the TRUNCATE TABLE statement.

To delete all rows in a partition without scanning bytes or consuming slots, see Using DML DELETE to delete partitions.

WHERE keyword

Each time you construct a DELETE statement, you must use the WHERE keyword, followed by a condition.

The WHERE keyword is mandatory for any DELETE statement.

DELETE examples

DELETE with WHERE clause

DELETEdataset.Inventory
WHEREquantity=0

Before: 

+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 20 | NULL |
| dryer | 30 | NULL |
| front load washer | 10 | NULL |
| microwave | 20 | NULL |
| oven | 5 | NULL |
| refrigerator | 10 | NULL |
| top load washer | 0 | NULL |
+-------------------+----------+--------------------+

After: 

+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 20 | NULL |
| dryer | 30 | NULL |
| front load washer | 10 | NULL |
| microwave | 20 | NULL |
| oven | 5 | NULL |
| refrigerator | 10 | NULL |
+-------------------+----------+--------------------+

DELETE with subquery

DELETEdataset.Inventoryi
WHEREi.productNOTIN(SELECTproductfromdataset.NewArrivals)

Before:

Inventory
+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 30 | NULL |
| dryer | 30 | NULL |
| front load washer | 20 | NULL |
| microwave | 20 | NULL |
| oven | 5 | NULL |
| refrigerator | 10 | NULL |
| top load washer | 10 | NULL |
+-------------------+----------+--------------------+
NewArrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 200 | warehouse #2 |
| oven | 300 | warehouse #3 |
| top load washer | 100 | warehouse #1 |
+-----------------+----------+--------------+

After:

Inventory
+-----------------+----------+--------------------+
| product | quantity | supply_constrained |
+-----------------+----------+--------------------+
| dryer | 30 | NULL |
| oven | 5 | NULL |
| top load washer | 10 | NULL |
+-----------------+----------+--------------------+

Alternately, you can use DELETE with the EXISTS clause:

DELETEdataset.Inventory
WHERENOTEXISTS
(SELECT*fromdataset.NewArrivals
WHEREInventory.product=NewArrivals.product)

TRUNCATE TABLE statement

The TRUNCATE TABLE statement removes all rows from a table but leaves the table metadata intact, including the table schema, description, and labels.

TRUNCATETABLE[[project_name.]dataset_name.]table_name

Where:

  • project_name is the name of the project containing the table. Defaults to the project that runs this DDL query.

  • dataset_name is the name of the dataset containing the table.

  • table_name is the name of the table to truncate.

Truncating views, materialized views, models, or external tables is not supported. Quotas and limits for queries apply to TRUNCATE TABLE statements. For more information, see Quotas and limits.

TRUNCATE TABLE examples

The following example removes all rows from the table named Inventory.

TRUNCATETABLEdataset.Inventory

UPDATE statement

Use the UPDATE statement when you want to update existing rows within a table.

UPDATEtarget_name[[AS]alias]
SETset_clause
[FROMfrom_clause]
WHEREcondition
set_clause::=update_item[,...]
update_item::=column_name=expression

Where:

  • target_name is the name of a table to update.
  • update_item is the name of column to update and an expression to evaluate for the updated value. The expression may contain the DEFAULT keyword, which is replaced by the default value for that column.

If the column is a STRUCT type, column_name can reference a field in the STRUCT using dot notation. For example, struct1.field1.

WHERE keyword

Each UPDATE statement must include the WHERE keyword, followed by a condition.

To update all rows in the table, use WHERE true.

FROM keyword

An UPDATE statement can optionally include a FROM clause.

You can use the FROM clause to specify the rows to update in the target table. You can also use columns from joined tables in a SET clause or WHERE condition.

The FROM clause join can be a cross join if no condition is specified in the WHERE clause, otherwise it is an inner join. In either case, rows from the target table can join with at most one row from the FROM clause.

To specify the join predicate between the table to be updated and tables in the FROM clause, use the WHERE clause. For an example, see UPDATE using joins.

Caveats:

  • The SET clause can reference columns from a target table and columns from any FROM item in the FROM clause. If there is a name collision, unqualified references are treated as ambiguous.
  • If the target table is present in the FROM clause as a table name, it must have an alias if you would like to perform a self-join.
  • If a row in the table to be updated joins with zero rows from the FROM clause, then the row isn't updated.
  • If a row in the table to be updated joins with exactly one row from the FROM clause, then the row is updated.
  • If a row in the table to be updated joins with more than one row from the FROM clause, then the query generates the following runtime error: UPDATE/MERGE must match at most one source row for each target row.

UPDATE examples

UPDATE with WHERE clause

The following example updates a table named Inventory by reducing the value of the quantity field by 10 for all products that contain the string washer. Assume that the default value for the supply_constrained column is set to TRUE.

UPDATEdataset.Inventory
SETquantity=quantity-10,
supply_constrained=DEFAULT
WHEREproductlike'%washer%'

Before:

Inventory
+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 30 | NULL |
| dryer | 30 | NULL |
| front load washer | 20 | NULL |
| microwave | 20 | NULL |
| oven | 5 | NULL |
| refrigerator | 10 | NULL |
| top load washer | 10 | NULL |
+-------------------+----------+--------------------+

After:

Inventory
+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 20 | true |
| dryer | 30 | NULL |
| front load washer | 10 | true |
| microwave | 20 | NULL |
| oven | 5 | NULL |
| refrigerator | 10 | NULL |
| top load washer | 0 | true |
+-------------------+----------+--------------------+

UPDATE using joins

The following example generates a table with inventory totals that include existing inventory and inventory from the NewArrivals table, and marks supply_constrained as false:

UPDATEdataset.Inventory
SETquantity=quantity+
(SELECTquantityFROMdataset.NewArrivals
WHEREInventory.product=NewArrivals.product),
supply_constrained=false
WHEREproductIN(SELECTproductFROMdataset.NewArrivals)

Alternately, you can join the tables:

UPDATEdataset.Inventoryi
SETquantity=i.quantity+n.quantity,
supply_constrained=false
FROMdataset.NewArrivalsn
WHEREi.product=n.product

Before:

Inventory
+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 30 | NULL |
| dryer | 30 | NULL |
| front load washer | 20 | NULL |
| microwave | 20 | NULL |
| oven | 5 | NULL |
| refrigerator | 10 | NULL |
| top load washer | 10 | NULL |
+-------------------+----------+--------------------+
NewArrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 200 | warehouse #2 |
| oven | 300 | warehouse #3 |
| top load washer | 100 | warehouse #1 |
+-----------------+----------+--------------+

After: 

+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 30 | NULL |
| dryer | 230 | false |
| front load washer | 20 | NULL |
| microwave | 20 | NULL |
| oven | 305 | false |
| refrigerator | 10 | NULL |
| top load washer | 110 | false |
+-------------------+----------+--------------------+

UPDATE nested fields

The following example updates nested record fields.

UPDATEdataset.DetailedInventory
SETspecifications.color='white',
specifications.warranty='1 year'
WHEREproductlike'%washer%'

Alternatively, you can update the entire record:

UPDATEdataset.DetailedInventory
SETspecifications
=STRUCT<colorSTRING,warrantySTRING,
dimensionsSTRUCT<depthFLOAT64,heightFLOAT64,widthFLOAT64>>('white','1 year',NULL)
WHEREproductlike'%washer%'

+----------------------+----------+--------------------+----------+---------------------------------------------------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+----------+---------------------------------------------------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [] | {"color":"white","warranty":"1 year","dimensions":null} |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [] | {"color":"white","warranty":"1 year","dimensions":null} |
| microwave | 20 | false | [] | NULL |
| oven | 5 | false | [] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | false | [] | {"color":"white","warranty":"1 year","dimensions":null} |
+----------------------+----------+--------------------+----------+---------------------------------------------------------+

UPDATE repeated records

The following example appends an entry to a repeated record in the comments column for products that contain the string washer:

UPDATEdataset.DetailedInventory
SETcomments=ARRAY(
SELECTcommentFROMUNNEST(comments)AScomment
UNIONALL
SELECT(CAST('2016-01-01'ASDATE),'comment1')
)
WHEREproductlike'%washer%'

+----------------------+----------+--------------------+----------------------------------------------------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+----------------------------------------------------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [u'{"created":"2016-01-01","comment":"comment1"}'] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [u'{"created":"2016-01-01","comment":"comment1"}'] | NULL |
| microwave | 20 | false | [] | NULL |
| oven | 5 | false | [] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | false | [u'{"created":"2016-01-01","comment":"comment1"}'] | NULL |
+----------------------+----------+--------------------+----------------------------------------------------+----------------+

Alternatively, you can use the ARRAY_CONCAT function:

UPDATEdataset.DetailedInventory
SETcomments=ARRAY_CONCAT(comments,
ARRAY<STRUCT<createdDATE,commentSTRING>>[(CAST('2016-01-01'ASDATE),'comment1')])
WHEREproductlike'%washer%'

The following example appends a second entry to the repeated record in the comments column for all rows:

UPDATEdataset.DetailedInventory
SETcomments=ARRAY(
SELECTcommentFROMUNNEST(comments)AScomment
UNIONALL
SELECT(CAST('2016-01-01'ASDATE),'comment2')
)
WHEREtrue
SELECTproduct,commentsFROMdataset.DetailedInventory

+----------------------+------------------------------------------------------------------------------------------------------+
| product | comments |
+----------------------+------------------------------------------------------------------------------------------------------+
| countertop microwave | [u'{"created":"2016-01-01","comment":"comment2"}'] |
| dishwasher | [u'{"created":"2016-01-01","comment":"comment1"}', u'{"created":"2016-01-01","comment":"comment2"}'] |
| dryer | [u'{"created":"2016-01-01","comment":"comment2"}'] |
| front load washer | [u'{"created":"2016-01-01","comment":"comment1"}', u'{"created":"2016-01-01","comment":"comment2"}'] |
| microwave | [u'{"created":"2016-01-01","comment":"comment2"}'] |
| oven | [u'{"created":"2016-01-01","comment":"comment2"}'] |
| refrigerator | [u'{"created":"2016-01-01","comment":"comment2"}'] |
| top load washer | [u'{"created":"2016-01-01","comment":"comment1"}', u'{"created":"2016-01-01","comment":"comment2"}'] |
+----------------------+------------------------------------------------------------------------------------------------------+

To delete repeated value entries, you can use WHERE ... NOT LIKE:

UPDATEdataset.DetailedInventory
SETcomments=ARRAY(
SELECTcFROMUNNEST(comments)ASc
WHEREc.commentNOTLIKE'%comment2%'
)
WHEREtrue

+----------------------+----------+--------------------+----------------------------------------------------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+----------------------------------------------------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [u'{"created":"2016-01-01","comment":"comment1"}'] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [u'{"created":"2016-01-01","comment":"comment1"}'] | NULL |
| microwave | 20 | false | [] | NULL |
| oven | 5 | false | [] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | false | [u'{"created":"2016-01-01","comment":"comment1"}'] | NULL |
+----------------------+----------+--------------------+----------------------------------------------------+----------------+

UPDATE statement using join between three tables

The following example sets supply_constrained to true for all products from NewArrivals where the warehouse location is in 'WA' state.

UPDATEdataset.DetailedInventory
SETsupply_constrained=true
FROMdataset.NewArrivals,dataset.Warehouse
WHEREDetailedInventory.product=NewArrivals.productAND
NewArrivals.warehouse=Warehouse.warehouseAND
Warehouse.state='WA'

Note that the join predicate for the join with the updated table (DetailedInventory) must be specified using WHERE. However, joins between the other tables (NewArrivals and Warehouse) can be specified using an explicit JOIN ... ON clause. For example, the following query is equivalent to the previous query:

UPDATEdataset.DetailedInventory
SETsupply_constrained=true
FROMdataset.NewArrivals
INNERJOINdataset.Warehouse
ONNewArrivals.warehouse=Warehouse.warehouse
WHEREDetailedInventory.product=NewArrivals.productAND
Warehouse.state='WA'

Before:

DetailedInventory
+----------------------+----------+--------------------+----------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+----------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [] | NULL |
| microwave | 20 | false | [] | NULL |
| oven | 5 | false | [] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | false | [] | NULL |
+----------------------+----------+--------------------+----------+----------------+
New arrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 200 | warehouse #2 |
| oven | 300 | warehouse #3 |
| top load washer | 100 | warehouse #1 |
+-----------------+----------+--------------+
Warehouse
+--------------+-------+
| warehouse | state |
+--------------+-------+
| warehouse #1 | WA |
| warehouse #2 | CA |
| warehouse #3 | WA |
+--------------+-------+

After: 

+----------------------+----------+--------------------+----------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+----------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [] | NULL |
| microwave | 20 | false | [] | NULL |
| oven | 5 | true | [] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | true | [] | NULL |
+----------------------+----------+--------------------+----------+----------------+

MERGE statement

A MERGE statement is a DML statement that can combine INSERT, UPDATE, and DELETE operations into a single statement and perform the operations atomically.

MERGE[INTO]target_name[[AS]alias]
USINGsource_name[[AS]alias]
ONmerge_condition
{when_clause}+
when_clause::=matched_clause|not_matched_by_target_clause|not_matched_by_source_clause
matched_clause::=WHENMATCHED[ANDsearch_condition]THEN{merge_update_clause|merge_delete_clause}
not_matched_by_target_clause::=WHENNOTMATCHED[BYTARGET][ANDsearch_condition]THENmerge_insert_clause
not_matched_by_source_clause::=WHENNOTMATCHEDBYSOURCE[ANDsearch_condition]THEN{merge_update_clause|merge_delete_clause}
merge_condition::=bool_expression
search_condition::=bool_expression
merge_update_clause::=UPDATESETupdate_item[,update_item]*
update_item::=column_name=expression
merge_delete_clause::=DELETE
merge_insert_clause::=INSERT[(column_1[,...,column_n])]input
input::=VALUES(expr_1[,...,expr_n])|ROW
expr::=expression|DEFAULT

Where:

  • target_name
    target_name is the name of the table you’re changing.
  • source_name
    source_name is a table name or subquery.
  • merge_condition

    A MERGE statement performs a JOIN between the target and the source. Then, depending on the match status (row matched, only in source table, only in destination table), the corresponding WHEN clause is executed. The merge_condition is used by the JOIN to match rows between source and target tables. Depending on the combination of WHEN clauses, different INNER and OUTER JOIN types are applied.

    If the merge_condition is FALSE, the query optimizer avoids using a JOIN. This optimization is referred to as a constant false predicate. A constant false predicate is useful when you perform an atomic DELETE on the target plus an INSERT from a source (DELETE with INSERT is also known as a REPLACE operation).

    If the columns used in the merge_condition both contain NULL values, specify something like X = Y OR (X IS NULL AND Y IS NULL). This lets you avoid the case where the join is based on two NULL values. NULL = NULL evaluates to NULL instead of TRUE, and creates duplicate rows in the results.

  • when_clause

    The when_clause has three options: MATCHED, NOT MATCHED BY TARGET and NOT MATCHED BY SOURCE. There must be at least one when_clause in each MERGE statement.

    Each when_clause can have an optional search_condition. The when_clause is executed for a row if both the merge_condition and search_condition are satisfied. When there are multiple qualified clauses, only the first when_clause is executed for a row.

  • matched_clause

    The matched_clause defines how to update or delete a row in the target table if that row matches a row in the source table.

    If there is at least one matched_clause performing an UPDATE operation, a runtime error is returned when multiple rows from the source table match one row from the target table, and you are trying to update or delete that row in the target table.

  • not_matched_by_target_clause
    The not_matched_by_target_clause defines how to insert into the target table if a row from source table does not match any row in the target table.
  • not_matched_by_source_clause
    The not_matched_by_source_clause defines how to update or delete a row in the target table if that row does not match any row in the source table.

Omitting column names

  • In the not_matched_by_target_clause, when the column names of target table are omitted, all columns in the target table are included in ascending order based on their ordinal positions. Note that, if the target table is an ingestion-time partitioned table, column names must be specified.
  • In the not_matched_by_target_clause, ROW can be used to include all the columns of the source in the ascending sequence of their ordinal positions. None of the pseudocolumns of the source are included. For example, the pseudocolumn _PARTITIONTIME is not included when the source is an ingestion-time partitioned table.

MERGE examples

Example 1

In the following example, the query adds new items from the Inventory table to the DetailedInventory table. For items with low inventory, the supply_constrained value is set to true, and comments are added.

MERGEdataset.DetailedInventoryT
USINGdataset.InventoryS
ONT.product=S.product
WHENNOTMATCHEDANDquantity < 20THEN
INSERT(product,quantity,supply_constrained,comments)
VALUES(product,quantity,true,ARRAY<STRUCT<createdDATE,commentSTRING>>[(DATE('2016-01-01'),'comment1')])
WHENNOTMATCHEDTHEN
INSERT(product,quantity,supply_constrained)
VALUES(product,quantity,false)

These are the tables before you run the query:

Inventory
+-------------------+----------+
| product | quantity |
+-------------------+----------+
| dishwasher | 30 |
| dryer | 30 |
| front load washer | 20 |
| microwave | 20 |
| oven | 5 |
| top load washer | 10 |
+-------------------+----------+

DetailedInventory
+----------------------+----------+--------------------+----------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+----------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| front load washer | 20 | false | [] | NULL |
| microwave | 20 | false | [] | NULL |
| refrigerator | 10 | false | [] | NULL |
+----------------------+----------+--------------------+----------+----------------+

This is the DetailedInventory table after you run the query:

DetailedInventory
+----------------------+----------+--------------------+-------------------------------------------------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+-------------------------------------------------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [] | NULL |
| microwave | 20 | false | [] | NULL |
| oven | 5 | true | [{"created":"2016-01-01","comment":"comment1"}] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | true | [{"created":"2016-01-01","comment":"comment1"}] | NULL |
+----------------------+----------+--------------------+-------------------------------------------------+----------------+

Example 2

In the following example, the query merges items from the NewArrivals table into the Inventory table. If an item is already present in Inventory, the query increments the quantity field. Otherwise, the query inserts a new row. Assume that the default value for the supply_constrained column is set to NULL.

MERGEdataset.InventoryT
USINGdataset.NewArrivalsS
ONT.product=S.product
WHENMATCHEDTHEN
UPDATESETquantity=T.quantity+S.quantity
WHENNOTMATCHEDTHEN
INSERT(product,quantity)VALUES(product,quantity)

These are the tables before you run the query:

NewArrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 20 | warehouse #2 |
| oven | 30 | warehouse #3 |
| refrigerator | 25 | warehouse #2 |
| top load washer | 10 | warehouse #1 |
+-----------------+----------+--------------+

Inventory
+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 30 | false |
| dryer | 30 | false |
| front load washer | 20 | false |
| microwave | 20 | false |
| oven | 5 | true |
| top load washer | 10 | true |
+-------------------+----------+--------------------+

This is the Inventory table after you run the query:

Inventory
+-------------------+----------+--------------------+
| product | quantity | supply_constrained |
+-------------------+----------+--------------------+
| dishwasher | 30 | false |
| dryer | 50 | false |
| front load washer | 20 | false |
| microwave | 20 | false |
| oven | 35 | true |
| refrigerator | 25 | NULL |
| top load washer | 20 | true |
+-------------------+----------+--------------------+

Example 3

In the following example, the query increases the quantity of products from warehouse #1 by 20 in the NewArrivals table. The query deletes all other products except for those from warehouse #2.

MERGEdataset.NewArrivalsT
USING(SELECT*FROMdataset.NewArrivalsWHEREwarehouse <> 'warehouse #2')S
ONT.product=S.product
WHENMATCHEDANDT.warehouse='warehouse #1'THEN
UPDATESETquantity=T.quantity+20
WHENMATCHEDTHEN
DELETE

This is the NewArrivals table before you run the query:

NewArrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 20 | warehouse #2 |
| oven | 30 | warehouse #3 |
| refrigerator | 25 | warehouse #2 |
| top load washer | 10 | warehouse #1 |
+-----------------+----------+--------------+

This is the NewArrivals table after you run the query:

NewArrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 20 | warehouse #2 |
| refrigerator | 25 | warehouse #2 |
| top load washer | 30 | warehouse #1 |
+-----------------+----------+--------------+

Example 4

In the following example, the query replaces all products like '%washer%' in the Inventory table by using the values in the NewArrivals table.

MERGEdataset.InventoryT
USINGdataset.NewArrivalsS
ONFALSE
WHENNOTMATCHEDANDproductLIKE'%washer%'THEN
INSERT(product,quantity)VALUES(product,quantity)
WHENNOTMATCHEDBYSOURCEANDproductLIKE'%washer%'THEN
DELETE

These are the tables before you run the query:

NewArrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 20 | warehouse #2 |
| refrigerator | 25 | warehouse #2 |
| top load washer | 30 | warehouse #1 |
+-----------------+----------+--------------+

Inventory
+-------------------+----------+
| product | quantity |
+-------------------+----------+
| dishwasher | 30 |
| dryer | 50 |
| front load washer | 20 |
| microwave | 20 |
| oven | 35 |
| refrigerator | 25 |
| top load washer | 20 |
+-------------------+----------+

This is the Inventory table after you run the query:

Inventory
+-----------------+----------+
| product | quantity |
+-----------------+----------+
| dryer | 50 |
| microwave | 20 |
| oven | 35 |
| refrigerator | 25 |
| top load washer | 30 |
+-----------------+----------+

Example 5

In the following example, the query adds a comment in the DetailedInventory table if the product has a lower than average quantity in Inventory table.

MERGEdataset.DetailedInventoryT
USINGdataset.InventoryS
ONT.product=S.product
WHENMATCHEDANDS.quantity < (SELECTAVG(quantity)FROMdataset.Inventory)THEN
UPDATESETcomments=ARRAY_CONCAT(comments,ARRAY<STRUCT<createdDATE,commentSTRING>>[(CAST('2016-02-01'ASDATE),'comment2')])

These are the tables before you run the query:

Inventory
+-----------------+----------+
| product | quantity |
+-----------------+----------+
| dryer | 50 |
| microwave | 20 |
| oven | 35 |
| refrigerator | 25 |
| top load washer | 30 |
+-----------------+----------+

DetailedInventory
+----------------------+----------+--------------------+-------------------------------------------------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+-------------------------------------------------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [] | NULL |
| microwave | 20 | false | [] | NULL |
| oven | 5 | true | [{"created":"2016-01-01","comment":"comment1"}] | NULL |
| refrigerator | 10 | false | [] | NULL |
| top load washer | 10 | true | [{"created":"2016-01-01","comment":"comment1"}] | NULL |
+----------------------+----------+--------------------+-------------------------------------------------+----------------+

This is the DetailedInventory table after you run the query: 

+----------------------+----------+--------------------+-----------------------------------------------------------------------------------------------+----------------+
| product | quantity | supply_constrained | comments | specifications |
+----------------------+----------+--------------------+-----------------------------------------------------------------------------------------------+----------------+
| countertop microwave | 20 | NULL | [] | NULL |
| dishwasher | 30 | false | [] | NULL |
| dryer | 30 | false | [] | NULL |
| front load washer | 20 | false | [] | NULL |
| microwave | 20 | false | [{"created":"2016年02月01日","comment":"comment2"}] | NULL |
| oven | 5 | true | [{"created":"2016年01月01日","comment":"comment1"}] | NULL |
| refrigerator | 10 | false | [{"created":"2016年02月01日","comment":"comment2"}] | NULL |
| top load washer | 10 | true | [{"created":"2016年01月01日","comment":"comment1"},{"created":"2016年02月01日","comment":"comment2"}] | NULL |
+----------------------+----------+--------------------+-----------------------------------------------------------------------------------------------+----------------+

Example 6

In the following example, the query increases the inventory of products from the warehouse in CA. The products from other states are deleted, and any product that is not present in the NewArrivals table is unchanged.

MERGEdataset.InventoryT
USING(SELECTproduct,quantity,stateFROMdataset.NewArrivalst1JOINdataset.Warehouset2ONt1.warehouse=t2.warehouse)S
ONT.product=S.product
WHENMATCHEDANDstate='CA'THEN
UPDATESETquantity=T.quantity+S.quantity
WHENMATCHEDTHEN
DELETE

These are the tables before you run the query: 

Warehouse
+--------------+-------+
| warehouse | state |
+--------------+-------+
| warehouse #1 | WA |
| warehouse #2 | CA |
| warehouse #3 | WA |
+--------------+-------+

NewArrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 20 | warehouse #2 |
| refrigerator | 25 | warehouse #2 |
| top load washer | 30 | warehouse #1 |
+-----------------+----------+--------------+

Inventory
+-----------------+----------+
| product | quantity |
+-----------------+----------+
| dryer | 50 |
| microwave | 20 |
| oven | 35 |
| refrigerator | 25 |
| top load washer | 30 |
+-----------------+----------+

This is the Inventory table after you run the query:

Inventory
+--------------+----------+
| product | quantity |
+--------------+----------+
| dryer | 70 |
| microwave | 20 |
| oven | 35 |
| refrigerator | 50 |
+--------------+----------+

Example 7

In the following example, a runtime error is returned because the query attempts to update a target table when the source contains more than one matched row. To resolve the error, you need to change the merge_condition or search_condition to avoid duplicate matches in the source.

MERGEdataset.InventoryT
USINGdataset.NewArrivalsS
ONT.product=S.product
WHENMATCHEDTHEN
UPDATESETquantity=T.quantity+S.quantity

These are the tables before you run the query:

NewArrivals
+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 10 | warehouse #2 |
| dryer | 20 | warehouse #1 |
| refrigerator | 25 | warehouse #2 |
| top load washer | 30 | warehouse #1 |
+-----------------+----------+--------------+

Inventory
+--------------+----------+
| product | quantity |
+--------------+----------+
| dryer | 70 |
| microwave | 20 |
| oven | 35 |
| refrigerator | 50 |
+--------------+----------+

When you run the query, the following error is returned:

UPDATE/MERGE must match at most one source row for each target row

Example 8

In the following example, all of the products in the NewArrivals table are replaced with values from the subquery. The INSERT clause does not specify column names for either the target table or the source subquery.

MERGEdataset.NewArrivals
USING(SELECT*FROMUNNEST([('microwave',10,'warehouse #1'),
('dryer',30,'warehouse #1'),
('oven',20,'warehouse #2')]))
ONFALSE
WHENNOTMATCHEDTHEN
INSERTROW
WHENNOTMATCHEDBYSOURCETHEN
DELETE

This is the NewArrivals table before you run the query:

+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| dryer | 10 | warehouse #2 |
| dryer | 20 | warehouse #1 |
| refrigerator | 25 | warehouse #2 |
| top load washer | 30 | warehouse #1 |
+-----------------+----------+--------------+

This is the NewArrivals table after you run the query:

+-----------------+----------+--------------+
| product | quantity | warehouse |
+-----------------+----------+--------------+
| microwave | 10 | warehouse #1 |
| dryer | 30 | warehouse #1 |
| oven | 20 | warehouse #2 |
+-----------------+----------+--------------+

Tables used in examples

The example queries in this document use the following tables.

Inventory table

[
{"name":"product","type":"string"},
{"name":"quantity","type":"integer"},
{"name":"supply_constrained","type":"boolean"}
]

DDL statement to create this table:

CREATEORREPLACETABLE
dataset.Inventory(productSTRING,
quantityINT64,
supply_constrainedBOOLEAN);

NewArrivals table

[
{"name":"product","type":"string"},
{"name":"quantity","type":"integer"},
{"name":"warehouse","type":"string"}
]

DDL statement to create this table:

CREATEORREPLACETABLE
dataset.NewArrivals(productSTRING,
quantityINT64,
warehouseSTRING);

Warehouse table

[
{"name":"warehouse","type":"string"},
{"name":"state","type":"string"}
]

DDL statement to create this table:

CREATEORREPLACETABLE
dataset.Warehouse(warehouseSTRING,
stateSTRING);

DetailedInventory table

[
{"name":"product","type":"string"},
{"name":"quantity","type":"integer"},
{"name":"supply_constrained","type":"boolean"},
{"name":"comments","type":"record","mode":"repeated","fields":[
{"name":"created","type":"date"},
{"name":"comment","type":"string"}
]},
{"name":"specifications","type":"record","fields":[
{"name":"color","type":"string"},
{"name":"warranty","type":"string"},
{"name":"dimensions","type":"record","fields":[
{"name":"depth","type":"float"},
{"name":"height","type":"float"},
{"name":"width","type":"float"}
]}
]}
]

DDL statement to create this table:

CREATEORREPLACETABLE
dataset.DetailedInventory(productSTRING,
quantityINT64,
supply_constrainedBOOLEAN,
commentsARRAY<STRUCT<createdDATE,commentSTRING>>,
specificationsSTRUCT<colorSTRING,warrantySTRING,
dimensionsSTRUCT<depthFLOAT64,heightFLOAT64,widthFLOAT64>>);

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Last updated 2025年11月24日 UTC.