Incorrect usage of UNION and ORDER BY

A common problem when using the UNION command in MySQL is when you want to order the sets of data differently. If you do it incorrectly, you will see the error message:

Incorrect usage of UNION and ORDER BY

To solve the problem, wrap each individual SELECT statement in parenthesis as follows:

{code type=php}
(SELECT col1,col2,col3 FROM table1 ORDER BY col2)
UNION
(SELECT cola,colb,colc FROM table2 ORDER BY cola)
{/code}

Nice and simple, all you have to do is remember the brackets!