How do I declare and use variables in Oracle?

Question

My main skills are with SQL Server, but I have been asked to do some tuning of an Oracle query. I have written the following SQL:

declare @startDate int
select @startDate = 20110501

And I get this error:

declare @startDate int
select @startDate = 20110501
Error at line 1
ORA-06550: line 1, column 9:
PLS-00103: Encountered the symbol "@" when expecting one of the following:
 begin function package pragma procedure subtype type use
 <an identifier> <a double-quoted delimited-identifier> form
 current cursor

How do I declare and use variables in Oracle?

• Fabio Marreco: oracle is pure pain

Answer 1

Inside pl/sql block:

declare
 startdate number;
begin
 select 20110501 into startdate from dual;
end;
/

using a bind variable:

var startdate number;
begin
 select 20110501 into :startdate from dual;
end;
/

PL/SQL procedure successfully completed.

SQL> print startdate
 STARTDATE
----------
 20110501

in a query:

select object_name 
from user_objects 
where created > to_date (:startdate,'yyyymmdd'); /*prefix the bind variable wïth ":" */

• Matthew: This unfortunately does not work for me. var my_num NUMBER; BEGIN SELECT 12345 INTO my_num FROM dual; END; / select * from my_table sa where sa.my_col = :my_num
• user953: what error do you get? (just tested and works)
• Matthew: I actually tried the solution posted by Jon of All Trades and that worked perfectly for my needs -- i.e. using DEFINE and referencing the variable with &.

Answer 2

SQL*Plus supports an additional format:

DEFINE StartDate = TO_DATE('2016-06-21');
DEFINE EndDate = TO_DATE('2016-06-30');
SELECT
 *
FROM
 MyTable
WHERE
 DateField BETWEEN &StartDate and &EndDate;

Note the ampersands where the substitutions are to be performed within the query.

• SherlockSpreadsheets: This worked for me in Toad for Oracle when using any of these functions: Execute as script or Execute via Toad script runner or Execute via SQL*Plus. However, if you try running with the Execute/compile statement at caret it returns an error message: "ORA-009000: invalid SQL statement".
• Wassadamo: Works in SQL Developer too.

Answer 3

In ORACLE SQL Developer 20.2.0.175, we can Run Script (F5):

DEFINE usr = 'YourName'; 
SELECT * FROM Department WHERE created_by = '&usr';