Hello,
I was recently surprised to find that EXTRACT's day of the week
numbering is different than TO_CHAR's ditto. EXTRACT starts at 0==Sunday
while TO_CHAR starts at 1==Sunday.
A suggestion for two documentation notes is attached as a patch to
current CVS HEAD.
--
Greetings from Troels Arvin, Copenhagen, Denmark
Index: doc/src/sgml/func.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql/doc/src/sgml/func.sgml,v
retrieving revision 1.229
diff -c -r1.229 func.sgml
*** doc/src/sgml/func.sgml 3 Dec 2004 18:34:31 -0000 1.229
--- doc/src/sgml/func.sgml 6 Dec 2004 10:16:57 -0000
***************
*** 4412,4417 ****
--- 4412,4424 ----
1230 microseconds = 2.021230 seconds.
</para>
</listitem>
+
+ <listitem>
+ <para><function>to_char</function>'s day of the week numbering
+ (see the 'D' formatting pattern) is different from that of the
+ <function>extract</function> function.
+ </para>
+ </listitem>
</itemizedlist>
</para>
***************
*** 5146,5151 ****
--- 5153,5163 ----
SELECT EXTRACT(DOW FROM TIMESTAMP '2001-02-16 20:38:40');
<lineannotation>Result: </lineannotation><computeroutput>5</computeroutput>
</screen>
+ <para>
+ Note that <function>extract</function>'s day of the week numbering is
+ different from that of the <function>to_char</function> function.
+ </para>
+
</listitem>
</varlistentry>
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