sequencial Join option

Y

Yossi evenzur

Hi
let's say i have 2 tables with identical structure, date and value for
example. These 2 tables contains overlapping data for example, the first
table ends at 30/04/2005 and the other one starts at 01/01/2005. there is no
option in the relationships to join 2 tables with the following : only
include rows where the join fields are not equal

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http://www.microsoft.com/office/com...3c9&dg=microsoft.public.access.tablesdbdesign
 
J

Jeff Boyce

Perhaps another approach would be to NOT use more than one table when the
data fields/structure is identical. You might do that if you were using a
spreadsheet, but it is not a good design when you're using a relational
database.

If the only difference between the two tables is the date range, use a
single table with the date field include (not range, date value).

Then use queries to "isolate" those date ranges of interest.

Good luck!

Regards

Jeff Boyce
Microsoft Office/Access MVP
 
J

Jeff Boyce

(and if this is data from an 'outside' source that you do not wish to import
into Access, take a look at a UNION query in Access HELP)

Regards

Jeff Boyce
Microsoft Office/Access MVP
 
C

Clifford Bass

Hi Yossi,

You are describing a form of a full outer join. However, if Jeff's
suggestion about date ranges do not apply due to records in the overlapping
date range including a mix of records, some in one table only, some in the
other table only and some in both tables, you can use a union of a couple of
queries that use left (or right) outer joins. Something like:

select a.*
from a left outer join b on b.key = a.key
where b.key is null
union
select b.*
from b left outer join a on a.key = b.key
where a.key is null

Hope that helps,

Clifford Bass
 
Y

Yossi evenzur

Hi, first, i don't have any control over the data table as it comes from
"outside". i wanted to see if you can add another type of "join", i'm well
familiar with SQL options, i simply don't know SQL very well. all other
suggestions are rather painful because i have to take 12 tables, cut the
useless dates and than paste them into 6 tables, each table has thousands of
rows and over 100 fields, so you can imagine the scope of work.
 

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