[SOLVED] Can't figure out last part of join

[tomdchi]

I have the query:

 

SELECT tblinvoiceitems.invoiceid, tblinvoices.id

FROM tblinvoiceitems

LEFT JOIN tblinvoices ON tblinvoiceitems.invoiceid = tblinvoices.id

 

This produces :

 

invoiceid  id 

6599 6599

6599 6599

6599 6599

6609 6609

6609 6609

6609 6609

6609 6609

6620 6620

6620 6620

6621 6621

6621 6621

6621 6621

6621 6621

6623 NULL

6624 NULL

6625 6625

7589 NULL

 

 

I need this to go further and retrun only records that have 'NULL' in the id column.  I have tried various ways but can't get it to work.  It would show only the 3 records from above with NULL:

 

invoiceid  id 

6623 NULL

6624 NULL

7589 NULL

 

Can anyone help me with this?

 

Thanks,

Tom

[xtopolis]

Perhaps:

SELECT tbi.invoiceid, ti.id 
FROM tblinvoiceitems tbi
LEFT JOIN tblinvoices ti
  ON (tbi.invoiceid = ti.id)
WHERE ti.id IS NULL

Untested

[tomdchi]

Perfect!  I was missing the () on the (tbi.invoiceid = ti.id)

[xtopolis]

actually, I think the () are optional in this case..

http://dev.mysql.com/doc/refman/5.0/en/join.html

 

at least it works~