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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>2.8. Updates</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="tutorial-agg.html" title="2.7. Aggregate Functions" /><link rel="next" href="tutorial-delete.html" title="2.9. Deletions" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">2.8. Updates</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="tutorial-agg.html" title="2.7. Aggregate Functions">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="tutorial-sql.html" title="Chapter 2. The SQL Language">Up</a></td><th width="60%" align="center">Chapter 2. The <acronym class="acronym">SQL</acronym> Language</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="tutorial-delete.html" title="2.9. Deletions">Next</a></td></tr></table><hr /></div><div class="sect1" id="TUTORIAL-UPDATE"><div class="titlepage"><div><div><h2 class="title" style="clear: both">2.8. Updates</h2></div></div></div><a id="id-1.4.4.9.2" class="indexterm"></a><p>
You can update existing rows using the
<code class="command">UPDATE</code> command.
Suppose you discover the temperature readings are
all off by 2 degrees after November 28. You can correct the
data as follows:
</p><pre class="programlisting">
UPDATE weather
SET temp_hi = temp_hi - 2, temp_lo = temp_lo - 2
WHERE date > '1994-11-28';
</pre><p>
</p><p>
Look at the new state of the data:
</p><pre class="programlisting">
SELECT * FROM weather;
city | temp_lo | temp_hi | prcp | date
---------------+---------+---------+------+------------
San Francisco | 46 | 50 | 0.25 | 1994-11-27
San Francisco | 41 | 55 | 0 | 1994-11-29
Hayward | 35 | 52 | | 1994-11-29
(3 rows)
</pre><p>
</p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="tutorial-agg.html" title="2.7. Aggregate Functions">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="tutorial-sql.html" title="Chapter 2. The SQL Language">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="tutorial-delete.html" title="2.9. Deletions">Next</a></td></tr><tr><td width="40%" align="left" valign="top">2.7. Aggregate Functions </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 2.9. Deletions</td></tr></table></div></body></html>
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