Hi Sergey, Jim

I tried the LEFT JOIN and it seemed to be working, then I started getting spurious results on certain data. Compare this with the previous SQL below(er):

SELECT DISTINCT NET.Operator, NET.Route, NET.Start_Date, NET.End_Date, NET.RorF, NET.Passengers, ;
	IIF( NET.Route == NET.Mcl_Rte, "    ", NET.Mcl_Rte) as ContrNum, NET.Family, ;
	0000000 AS CurrPass, 0000000 AS PrevPass, op.Desc as OpDesc, ;
	IIF( NET.Route == RF1.ERoute, RF1.ServType, "?") as ServeType ;	
  FROM NotETM NET ;
    JOIN Operator op ;
      On NET.Operator == op.Code ;
    LEFT JOIN RF1 ;
      On  NET.Operator == RF1.Operator ;
  WHERE (	 (	m.ldStartCurr BETWEEN NET.Start_date AND NET.End_date) ; ...

In this case there is just 1 NotETM (NET) record that meets the criteria for each operator
If we take Operator 54, it has an RF1 record for route 0604, with a servtype of " "
and ..............................RF1 record for route 0608, with a servtype of "D"

My results give 2 recs for each: 1 operator's with servetype of " " and "?" and the other's with
servetype of "?" and "D", but the passengers field is the same number in each case, and so it gets counted twice.

ALSO

I have to run through another similar table ETMDATA (to later get some average values to apply to NotETM data)

SELECT DISTINCT ET.Operator, ET.Route, ET.Class, ET.Date, ET.RorF, op.Desc as OpDesc, ;
	IIF( ET.Route == RF1.ERoute, RF1.ServType, "?") as ServeType, ;	
	IIF( ET.Route == ET.Mcl_Rte, "    ", ET.Mcl_Rte) as ContrNum, ET.Family, ;
	SUM( IIF( BETWEEN( ET.date, ldStartCurr, ldEndCurr), ET.Number, 0000000)) AS CurrPass, ;
	SUM( IIF( BETWEEN( ET.date, ldStartPrev, ldEndPrev), ET.Number, 0000000)) AS PrevPass ;
  FROM ETMData ET ;
    JOIN Operator op ;
      On ET.Operator == op.Code ;
    LEFT JOIN RF1 ;
      On ET.Operator == RF1.Operator ;
  WHERE (	  ( ET.date BETWEEN ldStartCurr and ldEndCurr) ;
        OR ( ET.date BETWEEN ldStartPrev and ldEndPrev) ); ...

but this, since I had to add the LEFT JOIN, now takes FOREVER. Obviously it's creating too big a dataset, or intermediate data, but I don't see why either code is taking so long or failing. I can't really trust this second SQL now.

Any ideas what's wrong?

REALLY appreciate it.

Terry

>You can use LEFT JOIN to get all records for the table on the left and NVL() to convrt NULLs to something else.
>
>>Please consider the SQL below.
>>The NET table is linked to the Route/Family table (RF1) by Operator and Route keys combo.
>>For each NET record I need to get its ServType code from the matching RF1 table rec.
>>BUT some NET recs don't have a matching RF1 rec, but still need to be reported.
>>
>>originally I just included RF1.ServType in the selection fields but NET recs with no matching RF1 weren't being reported. So I included the IIF() below (in the bigger picture)
>>
>>

>>    IIF(    NET.Operator == RF1.Operator ;
>>        and NET.Route    == RF1.ERoute, RF1.ServType, "?") as ServeType ;	
>>

>>
>>but this didn't work cos, I presume, if it didn't meet the join criteria on the RF1 table those recs weren't considered. So I took out the
>>
>>

>>      and NET.Route    == RF1.ERoute ;
>>

>>
>>from the join but now get duplicated instances. Bit flummoxed at the moment. ANy ideas?
>>
>>'ppreciate it.
>>
>>

>>SELECT NET.Operator, NET.Route, NET.Start_Date, NET.End_Date, NET.RorF, NET.Passengers, ;
>>       IIF( NET.Route == NET.Mcl_Rte, "    ", NET.Mcl_Rte) as ContrNum, NET.Family, ;
>>       0000000 AS CurrPass, 0000000 AS PrevPass, op.Desc as OpDesc, ;
>>       IIF(    NET.Operator == RF1.Operator ;
>>	  and NET.Route    == RF1.ERoute, RF1.ServType, "?") as ServeType ;	
>>  FROM NotETM NET ;
>>    JOIN Operator op ;
>>      On NET.Operator == op.Code ;
>>    JOIN RF1 ;
>>      On  NET.Operator == RF1.Operator ;
>>      and NET.Route    == RF1.ERoute ;
>> WHERE (	 ( m.ldStartCurr BETWEEN NET.Start_date AND NET.End_date) ;
>>        ...
>>
>>