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Displaying posts with tag: MySQL 5 (reset)
Joins in MySQL 5: #1054 – Unknown column ‘…’ in ‘on clause’

If you used to write MySQL joins for MySQL versions < 5.0 or upgrade your server from MySQL 4 to MySQL >= 5.0 you maybe run into a problem when you execute the following query:

FROM mytable1, mytable2
INNER JOIN mytable3
ON mytable1.mycolumnname = mytable3.mycolumnname

#1054 – Unknown column ‘mytable.mycolumnname’ in ‘on clause’

Even though you made sure that the column exists, the problem persists. It can be a very annoying and time-consuming task to track this kind of error down to it’s cause: MySQL starting from version 5.0 tries to be more compliant to ANSI SQL. The tables are beeing joined in a different order. The solution to this problem is actually very simple. Surround the tables in the FROM clause with round brackets:

FROM (mytable1, …
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