updating table

[Guest]

I am usingtwo tables
table1 tracks companies and there company codes. PK is company code
table2 tracks the companies transactions. PK is autonumber
when I run

SELECT Data.Symbol, Data.[Company Name], Data.Last, Data.Volume, Data.[Rel
Str], Data.Date
FROM Data LEFT JOIN Symbols ON Data.[Company Name] = Symbols.[Company Name]
WHERE (((Symbols.[Company Name]) Is Null));

I get 143 records how ever when I try to update or append I don't get that
number.
I think it is because I have multiple company codes table2 so if AA isn't in
table1 and it is in table2 4 times then it is trying to pull over more info
than it needs.

So can someone help?
Thanks,
RogueIT

 

[Michel Walsh]

Hi,


Indeed, if both tables have duplicated values, for a given match

Data.[Company Name] = Symbols.[Company Name]

say for company name = "Microsoft", there is n records in Data and m
records in Symbols, then the SELECT will generate n times m records, for
that company name value.

To stop that "explosion", you have to be sure that one of the table has NO
DUPLICATED values.



Hoping it may help,
Vanderghast, Access MVP