topic Re: Left Join in QlikView

Left Join

Mon, 11 Feb 2013 17:17:05 GMT

Hello,

I am trying to add 2 tables and map or left join the new fields to my resident table. However, I am finding that even with a left join my volume is increasing by 2.5 times. I was under the assumption a left join would solve this problem. The new tables I am "mapping" are only description fields. The [enctr id] is my key field. pg. 5 of the attched doc shows the script of my added tables. //***Sec Diag**** and //***Sec Proc***. If someone could make edits and attach a response I would greatly appreciate it.

Thank you,

Re: Left Join

rbecher — Mon, 11 Feb 2013 18:00:53 GMT

Hi EK,

this is hard to solve without any data. It would be better you would upload an example (with example data) as .qvw and the source files.

- Ralf

Re: Left Join

danielact — Mon, 11 Feb 2013 18:32:10 GMT

A left join won't necessarily mean the amount of records stays the same. For example, let's say you have these two tables:

Table1:

Col1 Col2

A W

B X

C Y

D Z

Table2:

Col1 Col3

A M

A N

A O

B P

B Q

B R

E S

E T

E U

If you load Table1 and do a left join with table2, you'll end up with this:

Col1 Col2 Col3

A W M

A W N

A W O

B X P

B X Q

B X R

C Y

D Z

Check in the second table for duplicate values. Using a Load Distinct can help you eliminate those.