select * from a
....+....1...
MYKEY MYDATA
A B
B C
select * from b
....+....1....+
MYKEY ITSDATA
A HI
1. An unspecified join seems to be equal to an inner join - data must
exist in both files.
SELECT A.MYKEY,A.MYDATA,B.ITSDATA FROM A
JOIN B USING (MYKEY)
and
SELECT A.MYKEY,A.MYDATA,B.ITSDATA FROM A
inner JOIN B USING (MYKEY)
both return only
....+....1....+....2..
MYKEY MYDATA ITSDATA
A B HI
2. LEFT JOIN seems to be equal to LEFT OUTER JOIN - pull from first/left
most file all
records and any matching (if any) from the second file
SELECT A.MYKEY,A.MYDATA,B.ITSDATA FROM A LEFT JOIN B USING (MYKEY)
....+....1....+....2..
MYKEY MYDATA ITSDATA
A B HI
B C -
SELECT A.MYKEY,A.MYDATA,B.ITSDATA FROM A
LEFT OUTER JOIN B USING (MYKEY)
....+....1....+....2..
MYKEY MYDATA ITSDATA
A B HI
B C -
3. Don't know if any of the tools in iNav will allow you to see where the
person is being dropped. But I have heard that the set of tools in iNav
are so darn good for analysis that one shop switched from SQL Server on
that basis alone.
Rob Berendt
