There are a number of ways to do this.
WHERE ‘something’ <> ‘something_else’
WHERE ‘something’ != ‘something_else’
As they are identical.
or you can specify a number of values you don’t want to be return from your column/field (my_tablein this example) – a more efficient way of doing things if you have a lot of values:
WHERE my_table NOT IN (‘something’, ‘something_else’);