Frequently Asked Questions (FAQ) for PostgreSQL
- Last updated: Wed Apr 18 23:05:05 EDT 2007
+ Last updated: Fri Apr 20 09:48:11 EDT 2007
Current maintainer: Bruce Momjian (bruce@momjian.us)
upper and lowercase characters, it can not have identical values that
differ only in case. To force a particular case to be stored in the
column, use a CHECK constraint or a trigger.
- 4.9) In a query, how do I detect if a field is NULL? How do I
- concatenate possible NULLs? How can I sort on whether a field is NULL
- or not?
4.9) In a query, how do I detect if a field is NULL? How do I concatenate
possible NULLs? How can I sort on whether a field is NULL or not?
alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
- <P>Last updated: Wed Apr 18 23:05:05 EDT 2007</P>
+ <P>Last updated: Fri Apr 20 09:48:11 EDT 2007</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:bruce@momjian.us">bruce@momjian.us</A>)
case to be stored in the column, use a <SMALL>CHECK</SMALL>
constraint or a trigger.</P>
- <A href="#item4.9">4.9</A>) In a query, how do I detect if a field
- is <SMALL>NULL</SMALL>? How do I concatenate possible <SMALL>NULL</SMALL>s?
- How can I sort on whether a field is <SMALL> NULL</SMALL> or not?<BR>
-
<H3 id="item4.9">4.9) In a query, how do I detect if a field
is <SMALL>NULL</SMALL>? How do I concatenate possible <SMALL>NULL</SMALL>s?
How can I sort on whether a field is <SMALL> NULL</SMALL> or not?</H3>