Question

How do I convert an integer to string as part of a PostgreSQL query?

So, for example, I need:

SELECT * FROM table WHERE <some integer> = 'string of numbers'

where <some integer> can be anywhere from 1 to 15 digits long.

Answer 1

Because the number can be up to 15 digits, you’ll need to cast to an 64 bit (8-byte) integer. Try this:

SELECT * FROM table
WHERE myint = mytext::int8

The :: cast operator is historical but convenient. Postgres also conforms to the SQL standard syntax

myint = cast ( mytext as int8)

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If you have literal text you want to compare with an int, cast the int to text:

SELECT * FROM table
WHERE myint::varchar(255) = mytext