multiple tables OR clause and with alias - mysql

Question

I need to query two columns "oc_filter_group_description.name" and "oc_filter.name" and get all matching results.
The alias seems to be causing me the problem. I've tried using a sub query but being a complete novice I really don't know what I'm doing.
Here is the code as it stands. The OR clause is what needs adapting
SELECT *,(SELECT name FROM oc_filter_group_description fgd
WHERE f.filter_group_id = fgd.filter_group_id) AS `group`
FROM oc_filter f LEFT JOIN oc_filter_description fd ON (f.filter_id = fd.filter_id)
WHERE fd.name LIKE '% **QUERY GOES HERE** %'
OR 'group' LIKE '% **QUERY GOES HERE** %'
I have spent far too long trying to get this to work I thought I better call in re-enforcements. Thanks in advance

Answer 1

You can't reference column aliases defined in the select in the where clause. This is your query:
SELECT *,
(SELECT name
FROM oc_filter_group_description fgd
WHERE f.filter_group_id = fgd.filter_group_id
) AS `group`
FROM oc_filter f LEFT JOIN
oc_filter_description fd
ON f.filter_id = fd.filter_id
WHERE fd.name LIKE '% **QUERY GOES HERE** %' OR
'group' LIKE '% **QUERY GOES HERE** %';
It has two obvious problems. The first is that 'group' is a string constant not a column reference. Only use single quotes for string literals. It avoids this type of problem. The second is that it refers to the group defined in the select clause.
The best solution is to replace the subquery in the select with another join:
SELECT *, fgd.name as group_name
FROM oc_filter f LEFT JOIN
oc_filter_description fd
ON f.filter_id = fd.filter_id LEFT JOIN
oc_filter_group_description fgd
ON f.filter_group_id = fgd.filter_group_id
WHERE fd.name LIKE '% **QUERY GOES HERE** %' OR
fgd.name LIKE '% **QUERY GOES HERE** %';
Note that I also changed the name group to group_name, so it doesn't conflict with a MySQL reserved words. Voila, no quotes are needed.

Answer 2

This might look a minor thing, but you shouldn't use backticks and whenever possible avoid keywords:
SELECT *, (
SELECT name FROM oc_filter_group_description fgd
WHERE f.filter_group_id = fgd.filter_group_id) AS T_GROUP
FROM oc_filter f LEFT JOIN oc_filter_description fd ON (f.filter_id = fd.filter_id)
WHERE fd.name LIKE '% **QUERY GOES HERE** %'
OR T_GROUP LIKE '% **QUERY GOES HERE** %'
Hope this helped.

Answer 3

You made it much more complicated than necessary. All you need is something like this:
select just the fields you need
from oc_filter f LEFT JOIN oc_filter_description fd ON (f.filter_id = fd.filter_id)
and (fd.name like '%static text goes here, not a query%'
or `group` like '%static text goes here, not a query%')
Notice that the filters are now part of the join as opposed to a where clause. If they were in a where clause, the left join would effectively become an inner join.