[Haskelldb-users] finding ids present in one table and not in another

[Guenther S. <gue...@we...>]

Hi guys,

I have this problem which I don't know how to solve:

I need to do something with records in one table whose Id is *not* 
present in another table like

testqry = do
  l1 <- table leistungIndices
  l2 <- table leistungIndices
  p  <- table procedureCnts
  restrict (l1!caseId .<>. p!caseId)
  restrict (l1!caseId .==. p!caseId)
  restrict (l1!caseId .==. l2!caseId)
  project (caseId << l1!caseId
           # fabId << l1!fabId
           # opLstgIdx << l1!opLstgIdx
           # opLstgIdxFab << _sum (l2!opLstgIdx))

which blows up because of the 1st restrict.

How can  I express this properly?

Günther