Outer Join, 2 columns

jking · December 5th, 2004, 01:13 AM

Do I understand correctly that outer joins are used when only one column uniquely identifies rows? I have seen other posts on this forum and others on outer joins, but those posts address a situation where only one column uniquely identifies each row.

I need to copy all rows from tblA that are not in tblB, into tblB.
TblA and TblB have same structure.
Rows are made unique by two columns: DateTime, ID

thanks,
jking

jemacc · December 5th, 2004, 04:14 AM

try something like this

Code:

UPDATE TblA 
SET TblA.Col1 =tblB.col1
WHERE NOT EXISTS (select ID from tblB WHERE TblB.id = TblA.id and tbla.datetime=tblb.datetime)

Jaime E. Maccou
Applications Analyst
Database Programmer