How to avoid Duplicate values for INSERT in SQL?

Question

I have one table named:

Delegates

This table has four fields:

ID(Auto increment, Primary)
MemberNo, FromYr, ToYr
         


        

Answer 1

Try this, (I have not verified)

INSERT INTO Delegates ([MemNo],[FromYr],[ToYr]) values(@MemNo, @FromYr,@ToYr)
where @MemNo not in 
(
    SELECT MemNo FROM words WHERE FromYr = @FromYr
)