Subject Re: [firebird-support] SQL Question
Author Svein Erling Tysvaer
Well, you do say that one tank can link to several nozzles. If a tank then
links to two nozzles which have the same values for LSold and MSold, then
they will appear to be duplicate records (since you do not select any
unique number in nozzles). As for grades, they will automatically be
duplicated for every tank having more than one nozzle.


At 15:54 22.07.2003 +0200, you wrote:
>Hi all,
>when I execute the following SQL, I get duplicates records. Anyone know why?
>There are 2 nozzles and 2 grades of fuel.
>SELECT T.Grade, G.Descrip,
>N.LSold as VolSold, N.MSold as MoneySold
>FROM Tanks T JOIN Nozzles N
>T.Number = N.Tank
>Grades G
>T.Grade = G.Grade_Num
>Order by T.Grade, G.Descrip