If I have a table two columns of which are as below:

C1 C2

-----------------

X Y

X Y

X Y

X Z

How can I just find the row that has a different value for column C2

given that all rows of interest have the same value for C1 (in the

above case the 4th row) ? My column types are integers for now. (I

have more columns in the table too that may have different values for

each of those rows if it looks like I'm storing duplicates..)

Thanks !