Question

I have a query that is working fine when I run in through phpMyAdmin directly as SQL, but when I try and do this in PHP it doesn’t work. I suspect the problem is because I’m trying to return a rownum value from a generated table and the SET command on the first line doesn’t work. Here is an example query that is working as expected as SQL:

SET @rownum =0;
SELECT * FROM (
    SELECT i.*, @rownum := @rownum +1 AS row,  (
        SELECT COUNT( * )FROM _votes WHERE i.id = image_id) AS total_votes, 
        (SELECT COUNT( * ) FROM _votes WHERE i.id = image_id AND voter_id = 67) AS voted 
        FROM _images AS i WHERE i.approved = 1 ORDER BY total_votes DESC ) 
    AS T WHERE entrant_id IN (68,69,70,71) 

(please forgive my formatting if it is incorrect)

Two things:

• Is this query too long and inefficient?
• How do I initialize the @rownum value to zero if this is coming from a php prepared statement?

I’ve tried adding JOIN (SELECT @rownum :=0) r to the end of the query but that doesn’t work.
Also I’ve tried this joining method unsuccessfully at various points within the query.

php

$query = "SELECT * FROM ( SELECT i.*, @rownum := ...

Answer 1

SET queries are distinct queries, and you can only send one query at a time through PHP. So, run the SET query, then run the second query. The MySQL server will remember your setting if you use the same connection.