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"Tom Discart" <nospam_tom.discart@pandora.be> schreef in bericht
news:XCzr9.3769$P93.497539197@hestia.telenet-ops.be...
> Ik zou graag een random recordset terugkrijgen uit een select op SQLServer
> 7.
> Het zou volgens
>
http://www.experts-exchange.com/Databases/Microsoft_SQL_Server/Q_10350443.ht
> ml#1 op deze manier kunnen.
> SELECT * FROM tablename ORDER BY RAND()
>
> Maar... bij mij krijg ik steeds dezelfde recordset terug.
> Hoe zou ik dit op kunnen oplossen?

Uit SQL Server Books Online:

A common way to generate random numbers from RAND is to include something
relatively variable as the seed value, such as adding several parts of a
GETDATE:

SELECT RAND( (DATEPART(mm, GETDATE()) * 100000 )
           + (DATEPART(ss, GETDATE()) * 1000 )
           + DATEPART(ms, GETDATE()) )

When you use an algorithm based on GETDATE to generate seed values, RAND can
still generate duplicate values if the calls to RAND are made within the
interval of the smallest datepart used in the algorithm. This is especially
likely if the calls to RAND are included in a single batch. Multiple calls
to RAND in a single batch can be executed within the same millisecond, which
is the smallest increment of DATEPART. In this case, incorporate a value
based on something other than time to generate the seed values.


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