/PRE
><P>
    (See also <A
HREF="queries-table-expressions.html#QUERIES-WHERE"
>Section 7.2.2</A
>.)
   </P
><P
>    If an arbitrary value expression is used in the select list, it
    conceptually adds a new virtual column to the returned table.  The
    value expression is evaluated once for each result row, with
    the row's values substituted for any column references.  But the
    expressions in the select list do not have to reference any
    columns in the table expression of the <TT
CLASS="LITERAL"