Question

Suppose I have two different ID’s assigned for same record. For example

RecordID | ID1 | ID2
--------------------
1        | X   | A
2        | X   | B
3        | Y   | C
4        | Y   | C
5        | Y   | D
6        | Z   | E
7        | Z   | E

Now, I want to get the records where ID1 is assigned to the same value where as ID2 is assigned to a different value.

For example, I want to get:

1, X, A
2, X, B

Here ID1 assigned it X where as ID2 assigned it A and B, two different values.

Is it possible to write a query in SQL or SQL server that will return such records?

Answer 1

You need to use a subquery where, for each row, you poke through the table and see if any other rows match a certain criteria related to it.

pseudo sql:

select 
      t1.id, 
      t1.variable, 
      t1.value 
   from 
      table t1 
   where 
      exists ( select 1 
                  from t2 
                  where t2.id != t1.id 
                    and t2.variable == t1.variable 
                    and t2.value != t1.value)