change column type from string to numeric

Question

so I have a table with 5.2 million records. 3 columns in this table are for salaries. Those column are currently stored as string and I'd like to change the data type to numeric (I understood while researching it that numeric is better than float).

I'm trying to run this command:

ALTER TABLE lca_test ALTER COLUMN prevailing_wage TYPE numeric(10,0)
USING prevailing_wage::numeric;

But I'm getting the error

ERROR: invalid input syntax for type numeric: "40768,43"

I'm not sure how I can make it work. Any idea?

• Erwin Brandstetter: Some sample values and your version of Postgres would help. Also, "string" is not a Postgres data type. Is it text or varchar or something else?

Answer 1

I'm ignorant of postgres SQL syntax, however this appears to be an issue with either the TYPE numeric(10,0) not containing decimal granularity (numeric(10,2)) would work, or the fact that the currency is in a european format that utilizes commas instead of decimals.

• Joe: If it's the format, see stackoverflow.com/q/8933782/143791 .

Answer 2

Replace the comma with a dot, which is the default "decimal point".

ALTER TABLE lca_test ALTER COLUMN prevailing_wage TYPE numeric(10,0)
USING translate(prevailing_wage, ',', '.')::numeric;

But as long as you are not going to store fractional digits (numeric(10,0)), you should really use integer (covers -2147483648 to [phone] or bigint (covers -9223372036854775808 to +9223372036854775807).

Or you really mean numeric(10,2) instead of numeric(10,0)?