Question

Is it possible in MySQL to update a single field and select multiple different fields all where a single condition is true, in a single query? I’m not exactly sure of what the proper SQL would be, but I want to merge these two example queries, if it is possible, of course.

Example

An update query:

UPDATE `users` SET `activation`='$activationCode' WHERE `email`='$anEmail'

and a select query:

SELECT `password`,`salt`,`fname`,`email` FROM `users` WHERE `email`='$anEmail'

See the duplicate condition here? Surely it’s unnecessary to query a MySQL database twice with duplicate conditions, when I could do it all at once under a single condition?

It’s worth noting that $anEmail and $activationCode would be previously defined variables in PHP (with the former also being exactly the same through both queries). Cheers.

Answer 1

You have to write a stored procedure.

delimiter ;;
CREATE PROCEDURE UpdateAndSelect (mEmail Varchar(50), mactivationCode Varchar(20))
 BEGIN
   START TRANSACTION;
   UPDATE `users` SET `activation`=mactivationCode WHERE `email`=mEmail;
   SELECT `password`,`salt`,`fname`,`email` FROM `users` WHERE `email`=mEmail;
   COMMIT;
 END;;
delimiter ;

Call the procedure with:

CALL UpdateAndSelect(:email, :activation)