mysql union different number of columns
mysql
Solution
You would want to select columns as `NULL` to take up for the empty space in certain tables.
Table A: (id, column1)
Table B: (id, column1, column2)
Select id, column1, null as column2 from tableA
UNION
Select id, column1, column2 from tableB
Problem
I know union queries have to have the same number of columns. I'm trying to get results from the table `comments` and results from the table `strings`, which has multiple joins. How do i this correctly? I haven't tested yet because i know i'll get an error with different number of columns. Here are the two queries that i'm trying to combine. query 1(strings) ``` SELECT sub.actionid as usersub, ftable.`last-time` as lastvisited, updatetable.recent as mostrecent, parent.* FROM `strings` as parent LEFT JOIN subscribe sub on sub.actionid=parent.id AND sub.userid=:userid JOIN followers ftable on ((ftable.sid=parent.sid AND ftable.page='1') OR (ftable.sid=parent.sid AND ftable.position=parent.position AND ftable.page='0') OR (ftable.profile=parent.starter AND parent.guideline='1')) AND ftable.userid=:userid JOIN `update-recent` updatetable on ((updatetable.sid=parent.sid AND updatetable.position=parent.position AND updatetable.pageid='0') OR (updatetable.profile=parent.starter) OR (updatetable.pageid=parent.pageid AND parent.pageid!=0)) WHERE ftable.userid=:userid AND parent.deleted='0' GROUP BY parent.id ``` query 2(comments) ``` SELECT * FROM comments WHERE viewed='0' AND (`starter-id`=:userid OR respondid=:userid) ``` I'd like to order the results by the timestamp column `posted` (most recent) `ORDER BY posted DESC` How do i union these queries?