3 Way join with different column names.

Hi,
I have 3 files each having 2 cols
e.g
File1
empid deptid
1 100
2 200
3 200
4 100
5 300
File2
empid salary
1 10
2 20
3 30
4 40
5 50
6 60
File3
deptid deptname
100 A
200 B
300 C
400 D
in the output i want total amt spent on each dept i.e A,B,C,D which would be a sum in rollup for each dept(100,200,300,400) salary of each employee.
So here i will have to join
File1.empid =File2.empid (which gives salaries) AND
File1.deptid = File3.deptid (which gives dept name)
So... in o/p i want dept_name and amt_spent_each_dept
My solution has
File1 ---
File2 ------[ JOIN] ---[Rollup] --- [File4 as output]
File3 ---
But what condition can i have in JOIN component to join these 3 tables ?

Questions by vital_parlsey   answers by vital_parlsey

Showing Answers 1 - 5 of 5 Answers

Mark Haynes

  • Mar 2nd, 2012
 

I believe what you are looking for is a query like this:

select f3.deptname dept_name, sum(isnull(f2.salary,0)) amt_spent_each_dept
from file3 f3 left join file1 f1 on (f3.deptid = f1.deptid)
left join file2 f2 on (f1.empid = f2.empid)
group by f3.deptname
order by f3.deptname

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vital_parlsey

  • Mar 3rd, 2012
 

Setup the join component- Fine .. I will answer this myself You don't need to mention a key here ..neither key nor override key So in the transform you have find the columns u need to match and put a condition for them in each column. so u may get a cartesian product and after that check it with a filter by expression where you don't need null (check this with is_valid or is_null) and then fwd it to sort where key is dept_id and then to roll up where key is again dept_id and roll up on sal So here you get your result for each dept expense.

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Malini

  • Apr 3rd, 2012
 

Code
  1.  

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PLMS

  • Mar 29th, 2013
 

Step 1: File1 - left outer Join {Key- empid} with -File2

Step 2: The above output flow should be sort{PBKS-if multifile} based on key empid

Step 3: The step 2s o/p flow to be left outer join {key: deptid} with -File 3

Step 4: In Rolloup-sum the the salary and map it to total_amt based on key deptid.

Step 5: FIle 4 will be ready now with required o/p (deptid,dept_name & total_amt)

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