Question

I have two tables:

TABLE 1
ID   VALUE   
1    ABC
2    DEF
3    GHI
4    JKL
5    XYZ

TABLE 2
ID  T1_ID  VALUE 
1   1      A
2   1      B
3   2      A
4   3      A
5   3      B
6   4      B 

I want to select all rows from TABLE 1 which have a TABLE 2 row for Values A AND B.
This would be rows 1 and 3 (not 2 because it has only A, not 4 because it has only B).
Can I do this without a subquery?

(Note: I also need to query against values in table 1 so I can’t just query table 2.)

Answer 1

Tadaaah! Without a subquery.

select distinct
  t1.*
from
  Table1 t1
  inner join Table2 t2a on t2a.t1_ID = t1.ID and t2a.VALUE = 'A'
  inner join Table2 t2b on t2b.t1_ID = t1.ID and t2b.VALUE = 'B'