On 01/15/2010 01:49 AM, Bart Joosen wrote:
>
> One way could be to first select only the unique ID's, sample this and then
> select only the relevant records:
>
> strQuery = "SELECT ID from tblFoo;"
> IDs <- sqlQuery(channel, strQuery)
> sample.IDs <- sample(IDs,10)
> strQuery = paste("SELECT ID from tblFoo WHRE ID IN(", sample.IDs, ");")
> IDs <- sqlQuery(channel, strQuery)Better is to use the built-in random() function in Postgres: #select count(*) from visits; count --------- 4846604 (1 row) # select count(*) from visits where random() < 0.005; count ------- 24391 (1 row) HTH, Joe
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