Question

Simple table

________________________________________________
| id | parent_id | name | some_condition_field |
------------------------------------------------

I want rowset:

________________________________________________________________________________
| id | name | count_childs_with_condition_one | count_childs_with_condition_two |
---------------------------------------------------------------------------------

It is possible? Variables, UNION’s etc..???

Answer 1

Here is a cross-platform solution:

For a single parent:

select count(case when some_condition_field = 'xxx' then 1 end) as CountXXX, 
    count(case when some_condition_field = 'yyy' then 1 end) as CountYYY
from MyTable
where parent_id = 123

For all parents:

select parent_id, 
    count(case when some_condition_field = 'xxx' then 1 end) as CountXXX, 
    count(case when some_condition_field = 'yyy' then 1 end) as CountYYY
from MyTable
group by parent_id

For MySQL, you could also use this syntax:

select parent_id, 
    count(if(some_condition_field = 'xxx', 1, null) as CountXXX, 
    count(if(some_condition_field = 'yyy', 1, null)) as CountYYY
from MyTable
group by parent_id