How to join multiple tables (Views: 30)
Problem/Question/Abstract: I am trying to connect a table in Delphi 3 (using Paradox) to receive data from multiple tables. Up till now, I thought using LEFT OUTER JOIN would do the trick, unfortunately, as soon as I hook up the third table, no data is send to the grid. The join has to be in a way of lookup. Answer: If your tables have the same struct (or you can force the same structure via SELECT) you can use UNION: SELECT * FROM Table1 UNION SELECT * FROM Table2 If your tables have different structs, try FULL OUTER JOIN instead of LEFT following from localsql.hlp: SELECT * FROM customer C FULL OUTER JOIN orders O on(C.custno = O.custno) FULL OUTER JOIN items I on(O.orderno = I.orderno) |