You can use an column alias in the select list of nested select statements. The column alias uses one of these forms:
column_heading = expression
expression column_heading
expression as column_heading
For example, this example is equivalent to a select statement with the as tableid clause removed:
1> select * 2> from syscolumns c 3> where c.id in ( 4> select o.id as tableid 5> from sysobjects o 6> where o.name like '%attr%')
Adaptive Server ignores the alias (the allowed column heading) in this example.
