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

Are the Spec field values non unique? This might explain why the query returns too many results; with duplicates you get get an effective cross product for those.