diff options
author | Bruce Momjian | 2003-05-28 04:35:28 +0000 |
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committer | Bruce Momjian | 2003-05-28 04:35:28 +0000 |
commit | a2b498c291d9c21474f128f37c89482908bf35b0 (patch) | |
tree | a649c8190581da1ad1a77a513bf75f19e1e1e372 | |
parent | a6f01d1aa684ef6aa0972a11648a7725a309c471 (diff) |
Add info about selecting a random row.
-rw-r--r-- | doc/FAQ | 12 | ||||
-rw-r--r-- | doc/src/FAQ/FAQ.html | 14 |
2 files changed, 20 insertions, 6 deletions
@@ -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> |