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authorBruce Momjian2003-05-28 04:35:28 +0000
committerBruce Momjian2003-05-28 04:35:28 +0000
commita2b498c291d9c21474f128f37c89482908bf35b0 (patch)
treea649c8190581da1ad1a77a513bf75f19e1e1e372
parenta6f01d1aa684ef6aa0972a11648a7725a309c471 (diff)
Add info about selecting a random row.
-rw-r--r--doc/FAQ12
-rw-r--r--doc/src/FAQ/FAQ.html14
2 files changed, 20 insertions, 6 deletions
diff --git a/doc/FAQ b/doc/FAQ
index c188796c0eb..234267d2814 100644
--- a/doc/FAQ
+++ b/doc/FAQ
@@ -1,7 +1,7 @@
Frequently Asked Questions (FAQ) for PostgreSQL
- Last updated: Mon May 26 15:25:04 EDT 2003
+ Last updated: Wed May 28 00:35:16 EDT 2003
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
@@ -58,7 +58,7 @@
Operational Questions
4.1) What is the difference between binary cursors and normal cursors?
- 4.2) How do I SELECT only the first few rows of a query?
+ 4.2) How do I SELECT only the first few rows of a query? A random row?
4.3) How do I get a list of tables or other things I can see in psql?
4.4) How do you remove a column from a table, or change it's data
type?
@@ -627,7 +627,7 @@
See the DECLARE manual page for a description.
- 4.2) How do I SELECT only the first few rows of a query?
+ 4.2) How do I SELECT only the first few rows of a query? A random row?
See the FETCH manual page, or use SELECT ... LIMIT....
@@ -637,6 +637,12 @@
evaluate only the first few records requested, or the entire query may
have to be evaluated until the desired rows have been generated.
+ To SELECT a random row, use:
+ SELECT col
+ FROM tab
+ ORDER BY random()
+ LIMIT 1;
+
4.3) How do I get a list of tables or other things I can see in psql?
You can read the source code for psql in file
diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html
index c63696aa587..23e7c92d06b 100644
--- a/doc/src/FAQ/FAQ.html
+++ b/doc/src/FAQ/FAQ.html
@@ -10,7 +10,7 @@
alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
- <P>Last updated: Mon May 26 15:25:04 EDT 2003</P>
+ <P>Last updated: Wed May 28 00:35:16 EDT 2003</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@@ -83,7 +83,7 @@
<A href="#4.1">4.1</A>) What is the difference between binary
cursors and normal cursors?<BR>
<A href="#4.2">4.2</A>) How do I <SMALL>SELECT</SMALL> only the
- first few rows of a query?<BR>
+ first few rows of a query? A random row?<BR>
<A href="#4.3">4.3</A>) How do I get a list of tables or other
things I can see in <I>psql</I>?<BR>
<A href="#4.4">4.4</A>) How do you remove a column from a
@@ -799,7 +799,7 @@
description.</P>
<H4><A name="4.2">4.2</A>) How do I <SMALL>SELECT</SMALL> only the
- first few rows of a query?</H4>
+ first few rows of a query? A random row?</H4>
<P>See the <SMALL>FETCH</SMALL> manual page, or use
<SMALL>SELECT</SMALL> ... <SMALL>LIMIT</SMALL>....</P>
@@ -811,6 +811,14 @@
records requested, or the entire query may have to be evaluated
until the desired rows have been generated.</P>
+ <P>To <SMALL>SELECT</SMALL> a random row, use:
+<PRE>
+ SELECT col
+ FROM tab
+ ORDER BY random()
+ LIMIT 1;
+</PRE>
+
<H4><A name="4.3">4.3</A>) How do I get a list of tables or other
things I can see in <I>psql</I>?</H4>