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	<title>Eric Fickes &#187; howto</title>
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		<title>Select random value from a range of values</title>
		<link>http://ericfickes.com/2010/01/select-random-value-from-a-range-of-values/</link>
		<comments>http://ericfickes.com/2010/01/select-random-value-from-a-range-of-values/#comments</comments>
		<pubDate>Sun, 03 Jan 2010 01:08:52 +0000</pubDate>
		<dc:creator>Eric Fickes</dc:creator>
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		<description><![CDATA[Earlier I blogged about creating random numbers using tsql functions.  Here are two techniques for selecting a random value from a pre-defined range of values in a tsql script.  The first technique uses a table variable ( MSSQL 2000 + &#8230; <a href="http://ericfickes.com/2010/01/select-random-value-from-a-range-of-values/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>Earlier I blogged about <a title="TSQL UDFs for generating random numbers" href="http://ericfickes.com/2009/09/generate-random-integers-using-tsql-udfs/" target="_blank">creating random numbers using tsql functions</a>.  Here are two techniques for selecting a random value from a pre-defined range of values in a tsql script.  The first technique uses a <a title="MSSQL 2000 let's you create table variables" href="http://msdn.microsoft.com/en-us/library/aa260638%28SQL.80%29.aspx" target="_blank">table variable</a> ( MSSQL 2000 + ), and the second uses a <a title="CTEs in MSSQL 2005 let you build queries a little differently" href="http://technet.microsoft.com/en-us/library/ms175972%28SQL.90%29.aspx" target="_blank">Common Table Expression</a> or CTE ( MSSQL 2005+ ).</p>
<h3>Select a random value using a table variable</h3>
<pre class="brush: sql; title: ; notranslate">

-- var to hold random integer
declare @field_val int

-- create table var to hold value range [ 0, 512, 1024, 2048, 4096 ]
-- inserting the first value sets the structure for the table variable
SELECT 0 AS 'num'
INTO #temp

-- insert data into table var
INSERT INTO #temp VALUES ( 512 )
INSERT INTO #temp VALUES ( 1024 )
INSERT INTO #temp VALUES ( 2048 )
INSERT INTO #temp VALUES ( 4096 )

-- assign random value
SELECT TOP 1 @field_val = num FROM #temp ORDER BY NEWID()

-- show value
SELECT @field_val

-- drop the table variable
DROP TABLE #temp
</pre>
<h3>Select a random value using a CTE</h3>
<pre class="brush: sql; title: ; notranslate">
-- define our data table
WITH data( car )
AS
(
	-- UNION together our range of values
	SELECT 'audi' AS 'car'
	UNION
	SELECT 'bmw' AS 'car'
	UNION
	SELECT 'infinity' AS 'car'
	UNION
	SELECT 'lexus' AS 'car'
	UNION
	SELECT 'porsche' AS 'car'
)
-- select a random value
SELECT TOP 1 car FROM data
ORDER BY NEWID()
</pre>
<p>Both of these techniques can be used with numbers or text.  Just be sure to mind your quotes, and variable datatypes.  Being able to pick a random value in data generation scripts has proven very useful.  I hope this helps somebody else out as well.</p>
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