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

问题

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.

回答1:

Because the number can be up to 15 digits, you'll meed 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)

---

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

回答2:

You can cast an integer to a string in this way

intval::text

and so in your case

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

回答3:

You could do this:

SELECT * FROM table WHERE cast(YOUR_INTEGER_VALUE as varchar) = 'string of numbers'

来源：https://stackoverflow.com/questions/13809547/how-do-i-convert-an-integer-to-string-as-part-of-a-postgresql-query