MySQL计算另一列=值的行

Question

I have a While loop that displays the COUNT of p.songid (post tracks) in each row. What I actually need is to get the count based on trackDeleted=0 instead of all the rows.

 SELECT u.username, u.id, u.score, s.genre, s.songid, s.songTitle, s.timeSubmitted, s.userid, s.insWanted, s.bounty, COUNT(p.songid)
 FROM  songs s
 LEFT JOIN users u ON u.id = s.userid
 LEFT JOIN posttracks p ON s.songid = p.songid
 WHERE paid=1 AND s.timeSubmitted >= ( CURDATE() - INTERVAL 60 DAY )
 GROUP BY s.timeSubmitted ASC
 LIMIT 25

Can I update the above query or does this have to be in a separate query?

Answer 1

I am not sure if this works in mySql but in SQL you are able to filter during the join as follows:

SELECT u.username, u.id, u.score, s.genre, s.songid, s.songTitle, s.timeSubmitted, s.userid, s.insWanted, s.bounty, COUNT(p.songid)
FROM  songs s
LEFT JOIN users u ON u.id = s.userid
LEFT JOIN posttracks p ON s.songid = p.songid and trackDeleted=0
WHERE paid=1 AND s.timeSubmitted >= ( CURDATE() - INTERVAL 60 DAY )
GROUP BY s.timeSubmitted ASC
LIMIT 25

Answer 2

Just in case anyone stumbles on this, as I did, the correct answer is probably something like:

SELECT u.username, u.id, u.score, s.genre, s.songid, s.songTitle, s.timeSubmitted, s.userid, s.insWanted, s.bounty, COUNT(IF(p.trackDeleted=0, 1, NULL)) as not_deleted_count
     FROM  songs s
     LEFT JOIN users u
     ON u.id = s.userid
     LEFT JOIN posttracks p
     ON s.songid = p.songid
     WHERE paid=1 AND s.timeSubmitted >= ( CURDATE() - INTERVAL 60 DAY )
     GROUP BY s.timeSubmitted ASC
     LIMIT 25

The key being COUNT(IF(p.trackDeleted=0, 1, NULL)) as not_deleted_count which will look at all the tracks in a grouping, and only count those that are not deleted.

Every other answer in here was mistaking the OP as only wanting to select tracks that werent deleted, when what he wanted was to count the number of tracks that werent deleted inside each grouping.

Answer 3

It depends in what table the trackDeleted column is.

If it lives in posttracks, then it's simple

SELECT COUNT(p.songid) FROM posttracks p where p.trackDeleted=0

Answer 4

Add trackDeleted = 0 to your WHERE clause:

...
WHERE paid=1 AND s.timeSubmitted >= ( CURDATE() - INTERVAL 60 DAY )
    AND trackDeleted=0
 --  ^^^ add this
GROUP BY s.timeSubmitted ASC
...

Answer 5

Try this... You must group by the p.songid.

 SELECT u.username, u.id, u.score, s.genre, s.songid, s.songTitle,
 s.timeSubmitted, s.userid, s.insWanted, s.bounty, COUNT(p.songid) FROM
 songs s LEFT JOIN users u ON u.id = s.userid LEFT JOIN posttracks p ON
 s.songid = p.songid WHERE paid=1 AND s.timeSubmitted >= ( CURDATE() -
 INTERVAL 60 DAY ) GROUP BY s.timeSubmitted ASC,p.songid LIMIT 25

Answer 6

If you are going to COUNT the song id, you must group it by it self, try this one.

 SELECT u.username, u.id, u.score, s.genre, s.songid, s.songTitle, s.timeSubmitted, s.userid, s.insWanted, s.bounty, COUNT(p.songid)
   FROM  songs s
   LEFT JOIN users u
     ON u.id = s.userid
   LEFT JOIN posttracks p
     ON s.songid = p.songid
  WHERE paid=1 
    AND s.timeSubmitted >= ( CURDATE() - INTERVAL 60 DAY )
    AND trackDeleted=0
  GROUP BY p.songid
  ORDER BY s.timeSubmitted
  LIMIT 25;

Answer 7

Either put your test in the join condition:

LEFT JOIN posttracks p
    ON s.songid = p.songid
    AND trackDeleted = 0

Or change COUNT(p.songid) to a SUM instead:

SUM(CASE WHEN (p.songid IS NOT NULL AND trackDeleted = 0) THEN 1 ELSE 0 END)

Answer 8

try this.

DECLARE @trackCount int,
SELECT u.username, u.id, u.score, s.genre, s.songid, s.songTitle, s.timeSubmitted, s.userid, s.insWanted, s.bounty,
 FROM songs s 
 LEFT JOIN users u ON u.id = s.userid 
 LEFT JOIN posttracks p ON s.songid = p.songid 
 WHERE paid=1 
 AND s.timeSubmitted >= ( CURDATE() - INTERVAL 60 DAY)
 GROUP BY s.timeSubmitted ASC
 LIMIT 25

 SELECT COUNT(p.songid) INTO @TrackCount
 FROM posttracks p
 WHERE p.trackDeleted = 0

try to add this to your code. just access local variable @trackcount if you need to show how many tracks have trackDeleted = 0.