Question

I’m a complete sql noob, so I apologize for the sql butchering that follows…
Here’s the pseudocode for what I’m trying to do:

count( 
   join( 
      select( * from table X where a='stuff' and b='junk' ) as X1
      select( * from table X where a='arg' and b='blarg' ) as X2
      select( * from table X where a='narf' and b='foo' ) as X3
   ) where X1.c = X2.c = X3.c
)

Is it possible to get this result in one query?

Answer 1

If I were to guess what you really want, it is the count of “c”s which have all three of the conditions in the a and b columns. If this is the case, the following works:

select count(*)
from (select c
      from table X
      group by c
      having sum(CASE WHEN a = 'stuff' AND b = 'junk' THEN 1 ELSE 0 END) > 0 and
             sum(CASE WHEN a = 'arg' AND b = 'blarg' THEN 1 ELSE 0 END) > 0 and
             sum(CASE WHEN a = 'narf' AND b = 'foo' THEN 1 ELSE 0 END) > 0
     ) t