On Tue, 2005-12-06 at 09:58 -0500, Tom Lane wrote: > Mario Splivalo <[EMAIL PROTECTED]> writes: > > Now I want all services which didn't have any messages within certain > > period: > > pulitzer2=# select * from services where id not in (select distinct > > service_id from messages where receiving_time between '2005-10-01' and > > '2005-10-30'); > > (0 rows) > > > Why is that? > > Probably, you've got some NULLs in the messages.service_id column ... > try excluding those from the sub-select.
Yes, I've discovered that later. Still, I'm confused with the 'biggies' at the bottom of my initial mail. I neglected to metion that I'm using postgresql 7.4.8. I discovered that I can create a FK on a column wich allows NULL values, and I can even insert rows with NULLs in FK column, although PK table where FK is pointing does not allow nuls. Is that 'by design', or...? Mike -- Mario Splivalo Mob-Art [EMAIL PROTECTED] "I can do it quick, I can do it cheap, I can do it well. Pick any two." ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings