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Retrieve data from 10 tables in QMF

 
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ruchi.jain

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Joined: 17 Sep 2007
Posts: 17
Location: Pune

PostPosted: Tue Sep 08, 2009 12:22 pm    Post subject: Retrieve data from 10 tables in QMF
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Hi All,

I want to retrieve data from 7 different tables. There is no condition we have to retrieve all the tables data.
It might be like that the user1 is in table1 but its not there in table2; but then also in our report we want that user.

I tried using UNION keyword but the limitation with UNION is that if we are retrieving 3 columns from table1 than from table2 we have to retrieve 3 columns only.
Can we use other function or keyword so that if the column numbers are mismatch then also we will able to get the data.

One more question, I tried with SPUFI but it is showing row limit exceeded. Apart from SPUFI/QMF how can i retrieve the data.

Appreciate your help.
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Ketan Varhade

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Joined: 29 Jun 2009
Posts: 197
Location: Mumbai

PostPosted: Tue Sep 08, 2009 12:28 pm    Post subject:
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HI Ruchi,
Please could you explain that on what basis that you want to the data for all the 7 table, is there any connection between the 7 tables, some key ?
Can you give us a example that how should be a desired output look like.

Have you tried using joins?
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ruchi.jain

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Joined: 17 Sep 2007
Posts: 17
Location: Pune

PostPosted: Tue Sep 08, 2009 1:03 pm    Post subject: Reply to: Retrieve data from 10 tables in QMF
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Hi Ketan,

There is no condition; we want to retrieve the data from all tables. One thing is that 5 tables have 1 column in common: Racfid is the column name.
Other 3 tables are not having this column but they are inter-related between them.

But i want the data like:

Table1 has 3 columns... table2 has 2 columns... table3 has 4 columns.... and so on...
if 1 user is in table1 but not in table2 then also i want the user1 in the report.

The report will contain all the columns name and if user detail is not there in particular column then it will give null value.
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enrico-sorichetti

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Joined: 14 Mar 2007
Posts: 10256
Location: italy

PostPosted: Tue Sep 08, 2009 1:14 pm    Post subject: Reply to: Retrieve data from 10 tables in QMF
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it would be wise to try to understand better the requirement...

from the confusing info provided the quick and dirty answer would be..
run as many queries as the tables You have

also get proper math training...
in the topic title You say 10 tables
in the topic text You say 7
afterward You contradict Yourself again by saying 5 and 3

sloppyness will not make people eager to help You

to get good help You need to post clearly what You have to do,
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ruchi.jain

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Joined: 17 Sep 2007
Posts: 17
Location: Pune

PostPosted: Tue Sep 08, 2009 1:56 pm    Post subject: Reply to: Retrieve data from 10 tables in QMF
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Hi,

Actually i want data of 10 tables only but i was just giving an example. Ketan asked are there any key column in all the tables so i am giving an example that if there are 8 tables then 5 are having 1 common column and other 3 are inter-related to them.

I am sorry if that misguide you but i really want to fetch data from 10 tables and out of them 7 are having 1 column common and other 3 are inter-related but with other column.

I want to give the data in 1 report only so running as much query as tables is not the feasible method.

I hope now you got the correct statistics.
Please help.
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GuyC

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Joined: 11 Aug 2009
Posts: 1281
Location: Belgium

PostPosted: Tue Sep 08, 2009 2:36 pm    Post subject:
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there are a few ways of full outer joining > 3 tables :

Basic : Nested outer join :
Code:

Select * from
(  Select first2.* ,c.*, coalesce(first2.K1, c.col1) as K1
     from
      (Select a.*,b.*, coalesce(a.col1,b.col1) as K1
         from table1 a
         full outer join table2 b on a.col1 = b.col1) as first2
     full outer join table3 c on c.col1 = first2.K1) as first3
full outer join table4 d on d.col1 = first3.K1


Easier : all in one
Code:
select *
 from           table1 a
full outer join table2 b on b.col1 = a.col1
full outer join table3 c on c.col1 = coalesce (a.col1,b.col1)
full outer join table4 d on d.col1 = coalesce (a.col1,b.col1,c.col1)
full outer join table5 e on e.col1 = coalesce (a.col1,b.col1,c.col1,d.col1)


If outer joining with different columns = combination of the above
suppose :
first 5 table outer join on col1
sixth table outer join on col2 which is also on table1,table3 and table5

Code:
select * from (

select a.*,b.*,c.*,d.*,e.*, coalesce (a.col2,c.col2,e.col2) as K2
 from           table1 a
full outer join table2 b on b.col1 = a.col1
full outer join table3 c on c.col1 = coalesce (a.col1,b.col1)
full outer join table4 d on d.col1 = coalesce (a.col1,b.col1,c.col1)
full outer join table5 e on e.col1 = coalesce (a.col1,b.col1,c.col1,d.col1)
) First5

full outer join table6 F on f.col2 = First5.K2

with very doubtfull results if a.col2 <> c.col2



PS.: you must understand that outer joining > 3 tables is not very performant, because for each 2 tables he must build an intermediate result
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sushanth bobby

Senior Member


Joined: 29 Jul 2008
Posts: 1013
Location: India

PostPosted: Tue Sep 08, 2009 2:46 pm    Post subject:
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Hi Ruchi,

Can you give us you sample data and the expected report output along with the query you have tried. It would be a lot helpfull.

Code:
    Try to use CODE tags while posting your sample data.


Thank You,
Sushanth
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sushanth bobby

Senior Member


Joined: 29 Jul 2008
Posts: 1013
Location: India

PostPosted: Tue Sep 08, 2009 2:48 pm    Post subject:
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Ha, i should have refreshed my page before posting.

Sushanth
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dick scherrer

Site Director


Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Wed Sep 09, 2009 12:32 am    Post subject:
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Hello,

If there is a large volume of data to be processed, you might consider unloading all of the data in some common format and doing what you need using the extracted data.

Running high volumes of data thru some poorly performing "query(ies)" will only waste system resources. . .
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