list</I
></TT
> ...</PRE
><P>
    (Instead of <TT
CLASS="LITERAL"
>DISTINCT</TT
> the key word <TT
CLASS="LITERAL"
>ALL</TT
>
    can be used to specify the default behavior of retaining all rows.)
   </P
><P
>    Obviously, two rows are considered distinct if they differ in at
    least one column value.  Null values are considered equal in this
    comparison.
   </P
><P
>    Alternatively, an arbitrary expression can determine what rows are
    to be considered distinct:
</P><PRE
CLASS="SYNOPSIS"
>SELECT