Consider the following table: 
 
   A  B  C  D
 
   4  5  1  7
   4  5  2  8
And the where clause being D = 7. Then your select would return just one line, and miss the C = 2. If you first select the A = 4, B = 5, and then go for the C, you get both lines.

Abigail

In reply to Re: Pipe the Output of a SQL statement into the Input of another by Abigail-II
in thread Pipe the Output of a SQL statement into the Input of another by johnirl

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