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Support for the Transact-SQL outer join operators *= and =* is deprecated and will be removed in a future release.
In accordance with ANSI/ISO SQL standards, SQL Anywhere supports the LEFT OUTER, RIGHT OUTER, and FULL OUTER keywords. For compatibility with Adaptive Server Enterprise before version 12, SQL Anywhere also supports the Transact-SQL counterparts of these keywords, *= and =*, providing the tsql_outer_joins database option is set to On.
There are some limitations and potential problems with the Transact-SQL semantics. For a detailed discussion of Transact-SQL outer joins, see the white paper "Semantics and Compatibility of Transact-SQL Outer Joins" at http://www.sybase.com/detail?id=1017447.
In the Transact-SQL dialect, you create outer joins by supplying a comma-separated list of tables in the FROM clause, and using the special operators *= or =* in the WHERE clause. In Adaptive Server Enterprise before version 12, the join condition must appear in the WHERE clause (ON was not supported).
When you are creating outer joins, do not mix *= syntax with ON clause syntax. This restriction also applies to views that are referenced in the query.
Transact-SQL outer join limitations
Views and Transact-SQL outer joins
How NULL affects Transact-SQL joins
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