Question

Is the following query

SELECT * FROM items WHERE field1 NOT LIKE '%a%' AND NOT LIKE '%b%' AND
NOT LIKE '%c%'

equivalent to

SELECT * FROM items WHERE field1 NOT IN ('a', 'b', 'c');

Generally speaking, which is the best way to exclude certain string values in a MySQL query?

Answer 1

Your first query:

SELECT * FROM items WHERE field1 NOT IN ('a', 'b', 'c');

is the same as this:

SELECT * FROM items WHERE field1 != 'a' AND field1 != 'b' AND field1 != 'c'

In that way, your two queries are NOT equivalent. Instead of your first query, you could also do something like this

SELECT * FROM items WHERE (field1 REGEXP '[abc]') = 0

See the manual about REGEXP for more info