ACC97: Outer Join Returns Wrong Records with ODBC Tables vs. Local Tables

You may get different results running a query that contains a WHERE clause and an outer join to another query on a local table than you get on an linked ODBC table. This happens even though the local table and the linked table contain the same data.

When the tables are local, the WHERE clause is processed before the outer join. However, when the tables are linked, the queries are combined into a single SQL statement and the WHERE clause is processed after the outer join.

To prevent this problem, the version of Microsoft Jet must be 3.51.2723.0 or later. To obtain a new version of Jet, install Microsoft Jet 3.51 Service Pack 2.

This problem was corrected in Microsoft Jet 3.51 Service Pack 2.

For additional information about Microsoft Jet 3.51 Service Pack 2, please see the following article in the Microsoft Knowledge Base:

Steps to Reproduce Behavior

1. Create a new database with the following tables and queries:

      Table: Table1
      -----------------
      Field Name: a
      Data Type: Number
   
      Field Name: b
      Data Type: Text
   
      Table: Table2
      -----------------
      Field Name: a
      Data Type: Number
   
      Field Name: c
      Data Type: Text
   
      Query: Query1
      -------------
      Field: a
      Table: Table2
   
      Field: c
      Table: Table2
      Criteria: "x"
   
      Query: Query2
      ------------------------------
      Join: Table1.[a] -> Query1.[a]
   
      Field: a
      Table: Table1
   
      Field: b
      Table: Table1
   
      Field: c
      Table: Query1
   					

2. Add the following records to Table1:

      a     b
      -------
      1     a
      2     b
      3     c 
   					

3. Add the following records to Table2:

      a     b
      -------
      1     x
      2     y
      3     z 
   					

4. Select Query2, and then click Open.
   
   Note that there are three records.
5. Export Table1 and Table2 to a SQL Server.
6. In the Access database, rename Table1 and Table2 to Table1_local and Table2_local, respectively.
7. Create a link to Table1 and Table2 on the SQL Server. You do not need to select a unique record identifier.
8. Rename the linked tables to Table1 and Table2.
9. Select Query2, and then click Open.
   
   Note that there is only one record.