Postgresql SELECT if string contains

Solution 1:

You should use 'tag_name' outside of quotes; then its interpreted as a field of the record. Concatenate using '||' with the literal percent signs:

SELECT id FROM TAG_TABLE WHERE 'aaaaaaaa' LIKE '%' || tag_name || '%';

Solution 2:

A proper way to search for a substring is to use position function instead of like expression, which requires escaping %, _ and an escape character (\ by default):

SELECT id FROM TAG_TABLE WHERE position(tag_name in 'aaaaaaaaaaa')>0;

Solution 3:

I personally prefer the simpler syntax of the ~ operator.

SELECT id FROM TAG_TABLE WHERE 'aaaaaaaa' ~ tag_name;

Worth reading through Difference between LIKE and ~ in Postgres to understand the difference. `