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SQL Anywhere 11.0.0 » SQL Anywhere Server - Database Administration » Configuring Your Database » Database options » Introduction to database options » Alphabetical list of options

 

extended_join_syntax option [database]

Controls whether queries with duplicate correlation names syntax for multi-table joins are allowed, or reported as an error.

Allowed values

On, Off

Default

On

Remarks

If this option is set to On, then SQL Anywhere allows duplicate correlation names to be used in the null-supplying side of outer joins. All tables or views specified with the same correlation name are interpreted as the same instance of the table or view.

The following FROM clause illustrates the SQL Anywhere interpretation of a join using duplicate correlation names where C1 and C2 are search conditions:

( R left outer join T on ( C1 ), T  join S on ( C2 ) )

If the option is set to On, this join is interpreted as follows:

( R left outer join T on ( C1 ) ) join S on ( C2 )

If the option is set to Off, the following error is generated:

SQL Anywhere Error -137: Table 'T' requires a unique correlation name.

Note

To see the result of eliminating duplicate correlation names, you can view the rewritten statement using the REWRITE function with the second argument set to ANSI.

See also