Michael Glaesemann wrote:
On Nov 24, 2005, at 21:21 , Marcus Engene wrote:
When we're having an alias discussion, I'd really like to see NVL
in postgres. Not because of porting from oracle as much as just
spelling that without the reference manual is completely impossible.
NVL: what a very unfortunate spelling. (NULL VaLue? NULL Valued
Logic? Named Very Loosely? Someone help me here :) ) AFAICT, COALESCE
is SQL standard, while NVL isn't. I think an index entry might be a
good idea.
Agreed, documentation patch applied to HEAD and 8.1.X.
--
Bruce Momjian| http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup.| Newtown Square, Pennsylvania 19073
Index: doc/src/sgml/func.sgml
===
RCS file: /cvsroot/pgsql/doc/src/sgml/func.sgml,v
retrieving revision 1.295
diff -c -c -r1.295 func.sgml
*** doc/src/sgml/func.sgml 19 Nov 2005 19:44:54 - 1.295
--- doc/src/sgml/func.sgml 28 Nov 2005 23:17:42 -
***
*** 7227,7232
--- 7227,7240
primaryCOALESCE/primary
/indexterm
+ indexterm
+primaryNVL/primary
+ /indexterm
+
+ indexterm
+primaryIFNULL/primary
+ /indexterm
+
synopsis
functionCOALESCE/function(replaceablevalue/replaceable optional,
.../optional)
/synopsis
***
*** 7234,7242
para
The functionCOALESCE/function function returns the first of its
arguments that is not null. Null is returned only if all arguments
!are null. This is often useful to substitute a
!default value for null values when data is retrieved for display,
!for example:
programlisting
SELECT COALESCE(description, short_description, '(none)') ...
/programlisting
--- 7242,7249
para
The functionCOALESCE/function function returns the first of its
arguments that is not null. Null is returned only if all arguments
!are null. It is often used to substitute a default value for
!null values when data is retrieved for display, for example:
programlisting
SELECT COALESCE(description, short_description, '(none)') ...
/programlisting
***
*** 7246,7252
Like a tokenCASE/token expression, functionCOALESCE/function will
not evaluate arguments that are not needed to determine the result;
that is, arguments to the right of the first non-null argument are
! not evaluated.
/para
/sect2
--- 7253,7261
Like a tokenCASE/token expression, functionCOALESCE/function will
not evaluate arguments that are not needed to determine the result;
that is, arguments to the right of the first non-null argument are
! not evaluated. This SQL-standard function provides capabilities similar
! to functionNVL/ and functionIFNULL/, which are used in some other
! database systems.
/para
/sect2
***
*** 7262,7277
/synopsis
para
!The functionNULLIF/function function returns a null value if and only
!if replaceablevalue1/replaceable and
!replaceablevalue2/replaceable are equal. Otherwise it returns
!replaceablevalue1/replaceable. This can be used to perform the
!inverse operation of the functionCOALESCE/function example
!given above:
programlisting
SELECT NULLIF(value, '(none)') ...
/programlisting
/para
/sect2
--- 7271,7289
/synopsis
para
!The functionNULLIF/function function returns a null value if
!replaceablevalue1/replaceable and replaceablevalue2/replaceable
!are equal; otherwise it returns replaceablevalue1/replaceable.
!This can be used to perform the inverse operation of the
!functionCOALESCE/function example given above:
programlisting
SELECT NULLIF(value, '(none)') ...
/programlisting
/para
+ para
+If replaceablevalue1/replaceable is literal(none)/, return a null,
+otherwise return replaceablevalue1/replaceable.
+ /para
/sect2
---(end of broadcast)---
TIP 5: don't forget to increase your free space map settings
