Mysql returns only one row when using Count

Question

Well I\'ve just hit a weird behaviour that I\'ve never seen before, or haven\'t noticed.

I\'m using this query:

  SELECT *, 
         COUNT(*) AS pag         


        

Answer 1

Yeah, the count is an aggregate operator, which makes only one row returned (without a group by clause)

Maybe make two separate queries? It doesn't make sense to have the row return the data and the total number of rows, because that data doesn't belong together.

If you really really want it, you can do something like this:

SELECT *, (select count(*) FROM notis WHERE cid=20) AS count FROM notis WHERE cid=20 ORDER BY nid DESC LIMIT 0,3

or this:

SELECT N.*, C.total from notis N join (select count(*) total FROM notis WHERE cid=20) C WHERE cid=20) AS count FROM notis WHERE cid=20 ORDER BY nid DESC LIMIT 0,3

With variances on the nested expression depending on your SQL dialect.

Answer 2

This is inefficient, but will work:

SELECT 
   *,
   (SELECT COUNT(*) FROM notis WHERE cid=20) AS pages
FROM notis 
WHERE cid=20 
ORDER BY nid DESC 
LIMIT 0,3

Answer 3

Using an aggregate function without a GROUP BY will always return one row, no matter what. You must use a GROUP BY if you want to return more than one row.

Note that on most RDBMS, such a query would have failed because it makes no sense.