Inner Joining the same table multiple times

Question

So I have received this error: #1066 - Not unique table/alias: \'Purchase\'

I am trying to do the following:

    SELECT Blank.BlankTypeCode
              


        

Answer 1

You need to use table aliases. You have mentioned the same table more than once in the from clause. The query is something like this:

SELECT b.BlankTypeCode, b.BlankCode, pa1.Amount, pa1.Type, p1.PurchaseDate, pa2.DatePaid
FROM Blank b
INNER JOIN Ticket t
ON b.BlankCode = t.Blank_BlankCode
INNER JOIN MCO_Blank mb
ON b.BlankCode = mb.Blank_BlankCode
INNER JOIN Purchase p1
ON  t.PurchaseID = p1.PurchaseID
INNER JOIN Purchase p2
ON mb.PurchaseID = p2.PurchaseID
INNER JOIN Payment pa1
ON t.PurchaseID = pa1.PurchaseID
INNER JOIN Payment pa2
ON mc.PurchaseID = pa2.PurchaseID
WHERE pa1.Status = "Paid";

I had to make a guess at which payment and purchase is intended for the aliases. These may not be correct in the from and where clauses.