Frequently Asked Questions (FAQ) for PostgreSQL
- Last updated: Thu Apr 26 20:55:41 EDT 2001
+ Last updated: Thu May 10 21:32:49 EDT 2001
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
4.11) What is an R-tree index?
4.12) What is the Genetic Query Optimizer?
4.13) How do I perform regular expression searches and
- case-insensitive regular expression searches?
+ case-insensitive regular expression searches? How do I use an index
+ for case-insensitive searches?
4.14) In a query, how do I detect if a field is NULL?
4.15) What is the difference between the various character types?
4.16.1) How do I create a serial/auto-incrementing field?
1.7) What is the latest release?
- The latest release of PostgreSQL is version 7.1.
+ The latest release of PostgreSQL is version 7.1.1.
We plan to have major releases every four months.
join queries through nonexhaustive search.
4.13) How do I perform regular expression searches and case-insensitive
- regular expression searches?
+ regular expression searches? How do I use an index for case-insensitive
+ searches?
The ~ operator does regular expression matching, and ~* does
case-insensitive regular expression matching. The case-insensitive
variant of LIKE is called ILIKE in PostgreSQL 7.1 and later.
+ Case-insensitive equality comparisons are normally expressed as:
+ SELECT *
+ FROM tab
+ WHERE lower(col) = 'abc'
+
+
+ This will not use an standard index. However, if you create a
+ functional index, it will be used:
+ CREATE INDEX tabindex on tab (lower(col));
+
+
4.14) In a query, how do I detect if a field is NULL?
You test the column with IS NULLIS NOT NULL.
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<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
- <P>Last updated: Thu Apr 26 20:55:41 EDT 2001</P>
+ <P>Last updated: Thu May 10 21:32:49 EDT 2001</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
<H4><A name="1.7">1.7</A>) What is the latest release?</H4>
- <P>The latest release of PostgreSQL is version 7.1.</P>
+ <P>The latest release of PostgreSQL is version 7.1.1.</P>
<P>We plan to have major releases every four months.</P>