It's just removing extra blank spaces, but this is un-necessary as SQL views empty strings as empty strings regardless how many spaces there are.

So if your query is trying to return only empty strings, then you dont need to trim.

The code below highlights this, if SQL considered

'' != ' '

the above to be true, then the penultimate select query would only return 1 row, but it returns 2.

CREATE TABLE trimTest (

value varchar(50)

)

INSERT INTO trimTest

VALUES (''),

(' ')

SELECT *

FROM trimTest

SELECT *

FROM trimTest

WHERE value = ''

SELECT *

FROM trimTest

WHERE LTRIM(RTRIM(value)) = ''