I composed this message once before but it seems to have gotten lost in
the ether. I ended up figuring this one out... I got Google lucky.
According to http://dev.mysql.com/doc/refman/5.0/en/join.html:
<Quote>
INNER JOIN| and |,| (comma) are semantically equivalent in the absence
of a join condition: both produce a Cartesian product between the
specified tables (that is, each and every row in the first table is
joined to each and every row in the second table).
However, the precedence of the comma operator is less than than of
|INNER JOIN|, |CROSS JOIN|, |LEFT JOIN|, and so on. If you mix comma
joins with the other join types when there is a join condition, an error
of the form |Unknown column '/|col_name|/' in 'on clause'| may occur.
Information about dealing with this problem is given later in this section.
</Quote>
and sure enough later in the document they explain it. Basically prior
to MySQL 5.0.12, Join and the comma operator were treated the same, but
in 5.0.12 and later, the join keyword has higher precedence than the
comma. So because the wanted pages code simplified is "... From
link,page Join page join nonempty ..." MySQLl joins the link table last
because it is joined by a comma rather than the join keyword.
The Solution:
in wiki/lib/WikiDB/backend/PearDB_mysql.php line 127:
Change
. " FROM $link_tbl,$page_tbl as linked "
To
. " FROM $link_tbl JOIN $page_tbl as linked "
-William Leader
-------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
|
