Question

This feels like it should be really easy, but I just can’t get it and I’ve tried everything.

How can I just get the NUMBER OF ROWS returned by this query:

(SELECT Alias1 . *, 
        Alias2 . * 
 FROM   Table1 AS Alias1 
        LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
 WHERE  Alias1.Col1 != 'blah1' 
        AND Alias1.Col2 LIKE 'blah2' 
        AND ( Alias1.Col3 LIKE 'blah3' 
               OR Alias1.Col3 LIKE 'blah4' ) 
        AND Alias1.Col4 = 'blah5' 
        AND Alias2.Col7 LIKE 'blah6' 
 ORDER  BY Alias1.Col6 DESC 
 LIMIT  50) 

UNION 

(SELECT Alias1 . *, 
        Alias2 . * 
 FROM   Table1 AS Alias1 
        LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
 WHERE  Alias1.Col1 != 'blah1' 
        AND Alias1.Col2 LIKE 'blah2' 
        AND ( Alias1.Col3 LIKE 'blah3' 
               OR Alias1.Col3 LIKE 'blah4' ) 
        AND Alias1.Col4 = 'blah5' 
        AND Alias2.Col5 LIKE 'blah6' 
 ORDER  BY Alias1.Col6 DESC 
 LIMIT  50) 

UNION 

(SELECT Alias1 . *, 
        Alias2 . * 
 FROM   Table1 AS Alias1 
        LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
 WHERE  Alias1.Col1 != 'blah1' 
        AND Alias1.Col2 LIKE 'blah2'
        AND ( Alias1.Col3 LIKE 'blah3' 
               OR Alias1.Col3 LIKE 'blah4' ) 
        AND Alias1.Col4 = 'blah5' 
 ORDER  BY Alias1.Col6 DESC 
 LIMIT  50) 

I suppose I could just use PHP to execute the query and then do a mysql_num_rows on the results, but I want to do it directly with SQL because I heard that’s faster as it saves a step.

Thanks!

EDIT:

The following is giving me error (#1060 – Duplicate column name ‘Col1’):

   SELECT COUNT(*) FROM (
   (SELECT Alias1 . *, 
            Alias2 . * 
     FROM   Table1 AS Alias1 
            LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
     WHERE  Alias1.Col1 != 'blah1' 
            AND Alias1.Col2 LIKE 'blah2' 
            AND ( Alias1.Col3 LIKE 'blah3' 
                   OR Alias1.Col3 LIKE 'blah4' ) 
            AND Alias1.Col4 = 'blah5' 
            AND Alias2.Col7 LIKE 'blah6' 
     ORDER  BY Alias1.Col6 DESC 
     LIMIT  50) 

    UNION 

    (SELECT Alias1 . *, 
            Alias2 . * 
     FROM   Table1 AS Alias1 
            LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
     WHERE  Alias1.Col1 != 'blah1' 
            AND Alias1.Col2 LIKE 'blah2' 
            AND ( Alias1.Col3 LIKE 'blah3' 
                   OR Alias1.Col3 LIKE 'blah4' ) 
            AND Alias1.Col4 = 'blah5' 
            AND Alias2.Col5 LIKE 'blah6' 
     ORDER  BY Alias1.Col6 DESC 
     LIMIT  50) 

    UNION 

    (SELECT Alias1 . *, 
            Alias2 . * 
     FROM   Table1 AS Alias1 
            LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
     WHERE  Alias1.Col1 != 'blah1' 
            AND Alias1.Col2 LIKE 'blah2'
            AND ( Alias1.Col3 LIKE 'blah3' 
                   OR Alias1.Col3 LIKE 'blah4' ) 
            AND Alias1.Col4 = 'blah5' 
     ORDER  BY Alias1.Col6 DESC 
     LIMIT  50)
   ) a

The following is giving me error (#1064 – You have an error in your SQL syntax; ):

 SELECT COUNT(*) FROM (
   (SELECT Alias1 . *, 
            Alias2 . * 
     FROM   Table1 AS Alias1 
            LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
     WHERE  Alias1.Col1 != 'blah1' 
            AND Alias1.Col2 LIKE 'blah2' 
            AND ( Alias1.Col3 LIKE 'blah3' 
                   OR Alias1.Col3 LIKE 'blah4' ) 
            AND Alias1.Col4 = 'blah5' 
            AND Alias2.Col7 LIKE 'blah6' 
     ORDER  BY Alias1.Col6 DESC 
     LIMIT  50) a

    UNION 

    (SELECT Alias1 . *, 
            Alias2 . * 
     FROM   Table1 AS Alias1 
            LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
     WHERE  Alias1.Col1 != 'blah1' 
            AND Alias1.Col2 LIKE 'blah2' 
            AND ( Alias1.Col3 LIKE 'blah3' 
                   OR Alias1.Col3 LIKE 'blah4' ) 
            AND Alias1.Col4 = 'blah5' 
            AND Alias2.Col5 LIKE 'blah6' 
     ORDER  BY Alias1.Col6 DESC 
     LIMIT  50) b

    UNION 

    (SELECT Alias1 . *, 
            Alias2 . * 
     FROM   Table1 AS Alias1 
            LEFT JOIN Table2 AS Alias2 USING ( Col1 ) 
     WHERE  Alias1.Col1 != 'blah1' 
            AND Alias1.Col2 LIKE 'blah2'
            AND ( Alias1.Col3 LIKE 'blah3' 
                   OR Alias1.Col3 LIKE 'blah4' ) 
            AND Alias1.Col4 = 'blah5' 
     ORDER  BY Alias1.Col6 DESC 
     LIMIT  50) c
   ) z

Answer 1

You need to specify a unique alias for your Column Col1 since it is used in a join which requires unique columns to match against each other. It will throw an error 1060 if it comes across duplicated columns. Check this: Duplicate column names in SQL query

In your case, the MySQL gets confused with Col1 in table 1 and table 2 and hence the error. Once you have used that, you can SELECT COUNT(*) from YourQuery