如何在没有临时表的情况下对子查询的结果进行UNION？

Question

I have a complex query which results in multiple columns which I want to UNION into a single column.

The naive UNION construct makes me place the FROM for each query to combine. I would like that FROM to be the result of the complex query.

I would like to say:

SELECT row1 AS result FROM (complex query)
UNION
SELECT row2 AS result FROM (same complex query)
UNION
SELECT row3 AS result FROM (same complex query)
...

How do I do that in MySQL 5.6.10 (I realize that CTE elegantly solves my problem), and without temp tables (my DBA is paranoid).

Answer 1

You can use a cte block like below:

with cte as
(
   complex query comes here
)
select row1 as result from cte
union
select row2 as result from cte
...

Using a temptable would be another alternative solution.

For more cte examples: http://www.mysqltutorial.org/mysql-cte/

EDIT: Since OP is using an older version, this is an alternative solution:

Use a #temp table like below in your main complex query:

Select ...
into #temp
from ...
...

Then, use the #temp table for union:

select row1 as result from #temp
union
select row2 as result from #temp