Question

I’m trying to calculate all the correct answer a user gets and update it in the score table. But it gives me a fun little error.

UPDATE score
SET end_time = CURTIME(), final_score = COUNT(
    SELECT *
    FROM answered
    WHERE (exam_id = 8 and student_login = 'user' and guessed = 1)
)
WHERE exam_id = 8 and student_login = 'user'

Error:

#1064 – You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near ‘SELECT * FROM answered WHERE (exam_id = 8 and student_login =
‘user’ and gue’ at line 3

This should be simple enough right? Then what is up with this error? The select works on its own. and the update works without the final_score update.

Thanks for the help!

Answer 1

UPDATE score
SET end_time = CURTIME(), final_score = (
    SELECT COUNT(*)
    FROM answered
    WHERE (exam_id = 8 and student_login = 'user' and guessed = 1)
)
WHERE exam_id = 8 and student_login = 'user'

Should do it.

COUNT cannot (as far as I know) operate on sub queries.