Where condition.

Question

I want to know that whether we can test a condition from a column which is not there in the query or not.

Answer 1

You can perform a WHERE filter on columns that you have either:

Selected FROM
Added with JOIN
Renamed or created using AS

If you are selecting a select number of columns you are indeed able to filter on the columns you have not selected.

example of above:

SELECT `title`, `body`, `date` FROM news WHERE `author` = 'Steve'

author is not returned in the result set but can be filtered on.

Answer 2

Nathan answered all you need, Sathak! Greetings.