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	<title>Random Snippets &#187; mysql</title>
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	<description>Random Snippets of Code for Web Developers</description>
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		<title>How to randomly order or select rows in a MySQL query</title>
		<link>http://www.randomsnippets.com/2008/10/28/how-to-randomly-order-or-select-rows-in-a-mysql-query/</link>
		<comments>http://www.randomsnippets.com/2008/10/28/how-to-randomly-order-or-select-rows-in-a-mysql-query/#comments</comments>
		<pubDate>Wed, 29 Oct 2008 06:04:46 +0000</pubDate>
		<dc:creator>Allen Liu</dc:creator>
				<category><![CDATA[mysql]]></category>
		<category><![CDATA[LIMIT]]></category>
		<category><![CDATA[mysql query]]></category>
		<category><![CDATA[ORDER]]></category>
		<category><![CDATA[query]]></category>
		<category><![CDATA[RAND]]></category>
		<category><![CDATA[random selection]]></category>
		<category><![CDATA[SELECT]]></category>

		<guid isPermaLink="false">http://www.randomsnippets.com/?p=188</guid>
		<description><![CDATA[I was looking for a way to order the rows randomly in a MySQL query and the solution was not easy for me to come by. I am posting the solution here in hopes of helping others. 1 2 3 &#8230; <a href="http://www.randomsnippets.com/2008/10/28/how-to-randomly-order-or-select-rows-in-a-mysql-query/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>I was looking for a way to order the rows randomly in a MySQL query and the solution was not easy for me to come by.  I am posting the solution here in hopes of helping others.</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
</pre></td><td class="code"><pre class="mysql" style="font-family:monospace;"><span style="color: #990099; font-weight: bold;">SELECT</span> <span style="color: #CC0099;">*</span> 
<span style="color: #990099; font-weight: bold;">FROM</span> my_table
<span style="color: #990099; font-weight: bold;">ORDER BY</span> <span style="color: #000099;">RAND</span><span style="color: #FF00FF;">&#40;</span><span style="color: #FF00FF;">&#41;</span></pre></td></tr></table></div>

<p><strong>RAND()</strong> returns a random floating-point value but functions to randomly order the selection of rows in the above usage.</p>
<p>If you combine the query with <strong>LIMIT</strong>, you will end up with a random selection of rows from your table.</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
</pre></td><td class="code"><pre class="mysql" style="font-family:monospace;"><span style="color: #990099; font-weight: bold;">SELECT</span> <span style="color: #CC0099;">*</span> 
<span style="color: #990099; font-weight: bold;">FROM</span> my_table
<span style="color: #990099; font-weight: bold;">ORDER BY</span> <span style="color: #000099;">RAND</span><span style="color: #FF00FF;">&#40;</span><span style="color: #FF00FF;">&#41;</span>
<span style="color: #990099; font-weight: bold;">LIMIT</span> <span style="color: #008080;">3</span></pre></td></tr></table></div>

<p>Assuming you have more than 3 rows in your table, you will always get 3 random rows from the query.</p>
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		</item>
		<item>
		<title>How to convert MySQL timestamp to PHP date type</title>
		<link>http://www.randomsnippets.com/2008/10/05/how-to-convert-mysql-timestamp-to-php-date-type/</link>
		<comments>http://www.randomsnippets.com/2008/10/05/how-to-convert-mysql-timestamp-to-php-date-type/#comments</comments>
		<pubDate>Mon, 06 Oct 2008 05:01:52 +0000</pubDate>
		<dc:creator>Allen Liu</dc:creator>
				<category><![CDATA[mysql]]></category>
		<category><![CDATA[php]]></category>
		<category><![CDATA[convert]]></category>
		<category><![CDATA[date function]]></category>
		<category><![CDATA[hh mm ss]]></category>
		<category><![CDATA[mysql timestamp]]></category>
		<category><![CDATA[parsing]]></category>
		<category><![CDATA[php date]]></category>
		<category><![CDATA[php strtotime]]></category>
		<category><![CDATA[query]]></category>
		<category><![CDATA[timestamp]]></category>
		<category><![CDATA[unix timestamp]]></category>

		<guid isPermaLink="false">http://www.randomsnippets.com/?p=131</guid>
		<description><![CDATA[Let&#8217;s say you have the following PHP code that extracts the date from the times table in your MySQL database. The date is of timestamp type which has the following format: &#8216;YYYY-MM-DD HH:MM:SS&#8217; or &#8217;2008-10-05 21:34:02.&#8217; 1 2 3 4 &#8230; <a href="http://www.randomsnippets.com/2008/10/05/how-to-convert-mysql-timestamp-to-php-date-type/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>Let&#8217;s say you have the following PHP code that extracts the <strong>date</strong> from the <strong>times</strong> table in your MySQL database.  The <strong>date</strong> is of <strong>timestamp</strong> type which has the following format: &#8216;YYYY-MM-DD HH:MM:SS&#8217; or &#8217;2008-10-05 21:34:02.&#8217;</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000088;">$res</span> <span style="color: #339933;">=</span> <span style="color: #990000;">mysql_query</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;SELECT date FROM times;&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">while</span> <span style="color: #009900;">&#40;</span> <span style="color: #000088;">$row</span> <span style="color: #339933;">=</span> <span style="color: #990000;">mysql_fetch_array</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$res</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
   <span style="color: #b1b100;">echo</span> <span style="color: #000088;">$row</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'date'</span><span style="color: #009900;">&#93;</span> <span style="color: #339933;">.</span> <span style="color: #0000ff;">&quot;&lt;br /&gt;&quot;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span></pre></td></tr></table></div>

<p><span id="more-131"></span><br />
This date format that is in the output is in the timestamp format, <code>2008-10-05 21:34:02</code>, which is not surprising, but you want something that is more &#8220;user-friendly&#8221; or &#8220;readable&#8221; as in <strong>&#8220;9:34 pm October 5, 2008.&#8221;</strong></p>
<p>Let&#8217;s go back to the drawing board and try again:</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000088;">$res</span> <span style="color: #339933;">=</span> <span style="color: #990000;">mysql_query</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;SELECT date FROM times;&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">while</span> <span style="color: #009900;">&#40;</span> <span style="color: #000088;">$row</span> <span style="color: #339933;">=</span> <span style="color: #990000;">mysql_fetch_array</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$res</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
   <span style="color: #b1b100;">echo</span> <span style="color: #990000;">date</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;g:i a F j, Y &quot;</span><span style="color: #339933;">,</span> <span style="color: #990000;">strtotime</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$row</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;date&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">.</span> <span style="color: #0000ff;">&quot;&lt;br /&gt;&quot;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span></pre></td></tr></table></div>

<p>A sample output from this PHP code would be <code>9:34 pm October 5, 2008</code> which is much more user-friendly.</p>
<p>The PHP <strong>strtotime</strong> function parses the MySQL timestamp into a Unix timestamp which can be utilized for further parsing or formatting in the PHP <strong>date</strong> function.</p>
<p>Here are some other sample date output formats that may be of practical use:</p>

<div class="wp_syntax"><table><tr><td class="line_numbers"><pre>1
2
3
4
5
6
</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #b1b100;">echo</span> <span style="color: #990000;">date</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;F j, Y g:i a&quot;</span><span style="color: #339933;">,</span> <span style="color: #990000;">strtotime</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$row</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;date&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>                  <span style="color: #666666; font-style: italic;">// October 5, 2008 9:34 pm</span>
<span style="color: #b1b100;">echo</span> <span style="color: #990000;">date</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;m.d.y&quot;</span><span style="color: #339933;">,</span> <span style="color: #990000;">strtotime</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$row</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;date&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>                         <span style="color: #666666; font-style: italic;">// 10.05.08</span>
<span style="color: #b1b100;">echo</span> <span style="color: #990000;">date</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;j, n, Y&quot;</span><span style="color: #339933;">,</span> <span style="color: #990000;">strtotime</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$row</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;date&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>                       <span style="color: #666666; font-style: italic;">// 5, 10, 2008</span>
<span style="color: #b1b100;">echo</span> <span style="color: #990000;">date</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;Ymd&quot;</span><span style="color: #339933;">,</span> <span style="color: #990000;">strtotime</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$row</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;date&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>                           <span style="color: #666666; font-style: italic;">// 20081005</span>
<span style="color: #b1b100;">echo</span> <span style="color: #990000;">date</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'\i\t \i\s \t\h\e jS \d\a\y.'</span><span style="color: #339933;">,</span> <span style="color: #990000;">strtotime</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$row</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;date&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>   <span style="color: #666666; font-style: italic;">// It is the 5th day.</span>
<span style="color: #b1b100;">echo</span> <span style="color: #990000;">date</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;D M j G:i:s T Y&quot;</span><span style="color: #339933;">,</span> <span style="color: #990000;">strtotime</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$row</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">&quot;date&quot;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>               <span style="color: #666666; font-style: italic;">// Sun Oct 5 21:34:02 PST 2008</span></pre></td></tr></table></div>

<p>If you found that my code was helpful in any way, shape, or form and would like to buy me a <strong>beer</strong>, please use the <strong>Donate</strong> button below =)  Cheers!</p>
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		<item>
		<title>How to count values with MySQL queries</title>
		<link>http://www.randomsnippets.com/2008/10/05/how-to-count-values-with-mysql-queries/</link>
		<comments>http://www.randomsnippets.com/2008/10/05/how-to-count-values-with-mysql-queries/#comments</comments>
		<pubDate>Mon, 06 Oct 2008 03:40:35 +0000</pubDate>
		<dc:creator>Allen Liu</dc:creator>
				<category><![CDATA[mysql]]></category>
		<category><![CDATA[alias]]></category>
		<category><![CDATA[column values]]></category>
		<category><![CDATA[count values]]></category>
		<category><![CDATA[counter]]></category>
		<category><![CDATA[loop through]]></category>
		<category><![CDATA[mysql queries]]></category>
		<category><![CDATA[mysql query]]></category>
		<category><![CDATA[query]]></category>
		<category><![CDATA[value]]></category>
		<category><![CDATA[vote counters]]></category>

		<guid isPermaLink="false">http://www.randomsnippets.com/?p=116</guid>
		<description><![CDATA[Let&#8217;s say you have the following table called votes that keeps track of how people voted and you want a query to count the number of votes for you instead of having to loop through all the rows with a &#8230; <a href="http://www.randomsnippets.com/2008/10/05/how-to-count-values-with-mysql-queries/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>Let&#8217;s say you have the following table called <strong>votes</strong> that keeps track of how people voted and you want a query to count the number of votes for you instead of having to loop through all the rows with a counter in PHP.  </p>
<table>
<tr>
<th>person</th>
<th>vote</th>
</tr>
<tr>
<td>obama</td>
<td>yes</td>
</tr>
<tr>
<td>mccain</td>
<td>no</td>
</tr>
<tr>
<td>obama</td>
<td>yes</td>
</tr>
<tr>
<td>obama</td>
<td>no</td>
</tr>
<tr>
<td>mccain</td>
<td>yes</td>
</tr>
<tr>
<td>obama</td>
<td>yes</td>
</tr>
<tr>
<td>obama</td>
<td>yes</td>
</tr>
<tr>
<td>obama</td>
<td>no</td>
</tr>
<tr>
<td>mccain</td>
<td>no</td>
</tr>
</table>
<p><span id="more-116"></span></p>
<p>Here is the MySQL query that would do just the job.<br />
<code><br />
SELECT person,<br />
SUM(IF(vote = "yes", 1,0)) AS `yes_votes`,<br />
SUM(IF(vote = "no", 1,0)) AS `no_votes`,<br />
COUNT(vote) AS `total`<br />
FROM votes<br />
GROUP BY person<br />
ORDER BY yes_votes DESC<br />
</code></p>
<p>The following would be the result of the query:</p>
<table>
<tr>
<th>person</th>
<th>yes_votes</th>
<th>no_votes</th>
<th>total</th>
</tr>
<tr>
<td>obama</td>
<td>4</td>
<td>2</td>
<td>6</td>
</tr>
<tr>
<td>mccain</td>
<td>1</td>
<td>2</td>
<td>3</td>
</tr>
</table>
<p>The beauty of the query all lies in the <strong>SUM IF</strong> statements.  For example, in order to count the <strong>yes</strong> votes, the IF statement will check to see if <strong>vote = &#8220;yes&#8221;</strong> as it loops through all the rows.  If so, the <strong>yes_votes</strong> column alias is incremented by <strong>1</strong>.  The same procedure goes for counting the no votes.  The <strong>COUNT</strong> statements keeps a tally on the total number of votes.  The <strong>GROUP BY person</strong> statement allows the vote counters to calculate the numbers by person instead of the total number of yes and no votes.  </p>
<p>Now, you do not have to loop through your MySQL results to count column values =)</p>
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