Join Properties window

Use the Join Properties window to change the type of an existing join and modify or specify the join condition.

The window contains the following fields:

  • Cartesian product. The Cartesian product is the result that is returned from two or more tables that are selected from, but not joined; that is, no join condition is specified. The output is all possible rows from all the tables selected from. For example, if you selected from two tables, the database would pair every row in the first table with every row in the second table. If each table had 6 rows, the Cartesian product would return 36 rows.

    If the SQL builder cannot insert an explicit join based on available information, it will default to a Cartesian product that is formed with the CROSS JOIN syntax in the FROM clause of the resulting SQL statement: FROM FirstTable CROSS JOIN SecondTable. You can also specify a Cartesian product by selecting the Cartesian product option in the Join Properties dialog box. The cross join icon is shown on the join.

  • Table join. Select the Table Join option to specify that your query will contain join condition for the two tables being joined. The Join Condition panel is enabled, allowing you to specify further details about the join.
  • Join Condition panel. This shows the expression that the join condition will contain. You can enter or edit the expression manually or you can use the menu button to the right of the panel to specify a natural join, open the Expression Editor, or open the Alternate relation dialog box.
  • Include. These fields allow you to specify that the join should be an outer join, where the result of the query should include the rows as specified by one of the following:
    • Select All rows from left table name to specify a left outer join
    • Select All rows from right table name to specify a right outer join
    • Select both All rows from left table name and All rows from right table name to specify a full outer join
  • Join Icon. This tells you the type of join you have specified.