Random sample by subgroup

Hi,

First, i'm a newbie with sql and i would like to do the following:

I want to extract a random sample for each value of a certain field in a table;

For example

table

clientid    name      group
1             xxx           a
2             yyy           b
3             ccc           c

etc...

and i would like a sample of 20% of the records for each group (a, b, c).... how can i do that...??

thanks! Received on Mon Oct 30 2006 - 13:02:56 CST