> select * from quotes where id=1+round(random()* cast ((select max(id) > from quotes) as double precision)); > id | quote | > author > -----+-----------------------------------------------------------+------ > ----------- > 187 | Vergib Deinen Feinden, aber vergiss niemals ihre Namen. | John > F. Kennedy > 377 | Die Wirklichkeit ist nicht so oder so, sondern so und so. | Harry > Mulisch > (2 rows) > > I'm not really into databases, but this sounds wrong. Most of the time, > I actually get 0 results.
Random is calculated per call (in this case per comparison). So, the value you compare against for 187 is not the same as 377. UPDATE table SET column = random(); will show the effect. If you wrap randon() in a subselect, it will cause it to be evaluated once: SELECT * from quotes where id = 1+round((SELECT random()) * cast(....). However, a much faster query for your purposes would be: SELECT * FROM quotes ORDER BY random() LIMIT 1;
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