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Anton Alexandrov
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Fri, 29 Aug 2003 14:19:22 GMT
Different results with different consistency of JOIN clauses
Hi all,
I am working with Delphi 4 and local SQL. I don't understand what is the precedence of JOIN clauses in SQL statements. I notice that I receive the different result for the next two sql statements: The difference between those two statements is only in consistency of JOIN clauses. First statement: SELECT Table1."Field1", Table2."Field2_2" , Table3."Field3_2", Table1."Field2 FROM "Oborot.DB" Table1 INNER JOIN "Protokol.DB" Protokol ON (Table1."Field0" = Protokol."Field0) LEFT OUTER JOIN "Document.DB" Table2 ON (Table1."Field4" = Table2."Field2_1") LEFT OUTER JOIN "Document.DB" Table3 ON (Table1."Field5" = Table3."Field3_1") WHERE (Protokol.Type = 2) AND ( Table1.Data < "01/01/2001") AND ( Table1.Data > "12/31/1999") Second statement: SELECT Table1."Field1", Table2."Field2_2" , Table3."Field3_2", Table1."Field2 FROM "Oborot.DB" Table1 LEFT OUTER JOIN "Document.DB" Table2 ON (Table1."Field4" = Table2."Field2_1") LEFT OUTER JOIN "Document.DB" Table3 ON (Table1."Field5" = Table3."Field3_1") INNER JOIN "Protokol.DB" Protokol ON (Table1."Field0" = Protokol."Field0) WHERE (Protokol.Type = 2) AND ( Table1.Data < "01/01/2001") AND ( Table1.Data > "12/31/1999") I know the precedence of logical operations but I don't know the precedence of JOIN clauses. Please help me Anton |