Editing Troubleshooting of MySQL errors (section)

=== ERROR 1054 - Unknown column in 'where clause' ===
Message: [Err] 1054 - Unknown column 'xxx' in 'where clause'

Solution:
# check the column name 'xxx' if exists
# if the column name 'xxx' was computed by the [http://dev.mysql.com/doc/refman/5.7/en/example-user-variables.html User-Defined Variables]. Enclosed the whole query into another parent derived query.
<pre>
-- The query which met the error message: [Err] 1054 - Unknown column 'rank' in 'where clause'
SELECT semi.*, IF(semi.id = semi.prev, @rank := @rank +1, @rank := 1 ) AS `rank`   
FROM
(
        ...
) semi
WHERE semi.rank <= 10
</pre>

Enclosed the whole query into another parent derived query.
<pre>
SELECT final.*
FROM
(
        SELECT semi.*, IF(semi.id = semi.prev, @rank := @rank +1, @rank := 1 ) AS `rank`   
        FROM
        (
                ...
        ) semi
) final
WHERE final.rank <= 10
</pre>