SQL Inner Join Returns WAY More Rows Than Expected

Question

The following query returns >7000 rows when each table only has 340 rows.

SELECT Config.Spec, TempTable.Spec FROM Confg INNER JOIN TempTable on Config.Spec = Tem         


        

Answer 1

If there is more than one row with the same Spec value in TempTable for the same Spec value in Confg, then you will get duplicate rows, and vice versa.