On Fri, 19 Nov 2004 15:01:42 -0500, Tom Lane <[EMAIL PROTECTED]> wrote: > Don Drake <[EMAIL PROTECTED]> writes: > > This is still strange to me. In Oracle, the same query would not > > replace the *entire* string with a NULL, it treats the NULL as a no > > value. > > Oracle is a bit, um, standards-challenged. They fail to make a > distinction between an empty string and a NULL, but such a distinction > is both logically necessary and required by the SQL standard. > > > I can't find in the documentation where string concatenation of any > > string and NULL is NULL. > > SQL92 section 6.13 <string value expression>, General Rule 2a: > > a) If either S1 or S2 is the null value, then the result of the > <concatenation> is the null value. > > regards, tom lane >
Thanks for the responses. I now have a better appreciation for the SQL standard and PostgreSQL. -Don ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
