SQL error during tag cron process to cache tag correlations. In tag/lib.php function tag_compute_correlations()

MySQL 4.1.22 responds with : ERROR 1111 (HY000): Invalid use of group function to queries in the following format:

SELECT tb.tagid FROM mdl_tag_instance ta INNER JOIN mdl_tag_instance tb ON ta.itemid = tb.itemid WHERE ta.tagid = 2 AND tb.tagid != 2 GROUP BY tb.tagid HAVING COUNT > 2 ORDER BY COUNT DESC;

This appears to be a limitation of MySQL 4.x where group by using aggregate functions fails unless it appears as an alias in select clause.

See discussion here: http://bugs.mysql.com/bug.php?id=5478

This can be made to work as follows

SELECT tb.tagid, COUNT AS nr FROM mdl_tag_instance ta INNER JOIN mdl_tag_instance tb ON ta.itemid = tb.itemid WHERE ta.tagid = 2 AND tb.tagid != 2 GROUP BY tb.tagid HAVING nr > 2 ORDER BY nr DESC;

Suggested patches for 1.9.7 and 2.0 attached.

PHP Notice: Invalid use of group function<br /><br />SELECT tb.tagid FROM mdl_tag_instance ta INNER JOIN mdl_tag_instance tb ON ta.itemid = tb.item
id WHERE ta.tagid = 10 AND tb.tagid != 10 GROUP BY tb.tagid HAVING COUNT > 2 ORDER BY COUNT DESC<ul style="text-align: left"><li>line 686 of lib/dmllib.php: call to debugging()</li><li>line 966
of lib/dmllib.php: call to get_recordset_sql()</li><li>line 784 of tag/lib.php: call to get_records_sql()</li><li>line 816 of tag/lib.php: call to tag_compute_correlations()</li><li>line 369 of admin/c
ron.php: call to tag_cron()</li></ul> in /websites/mysupa-19/lib/weblib.php on line 6994