topic join vs concat in qliview data modelling in QlikView

join vs concat in qliview data modelling

sonikajain — Fri, 01 Jun 2012 04:43:21 GMT

Dear all,

I have come across 2 techiniques for data modelling - join and concat. Can anyone please help me understand when to use which and the advantages and pitfalls of each......

Thanks

join vs concat in qliview data modelling

Sokkorn — Fri, 01 Jun 2012 04:55:01 GMT

Hi,

Read this threads:

http://qlikviewnotes.blogspot.com/2009/11/understanding-join-and-concatenate.html

http://community.qlik.com/message/220074

http://community.qlik.com/message/138084

http://www.qlikfix.com/2010/12/09/merging-tables-concatenation/

Hope this help.

Regards,

Sokkorn

Re: join vs concat in qliview data modelling

jonathandienst — Fri, 01 Jun 2012 07:15:33 GMT

To put it simply, Concat adds new rows to the table, while Join adds new columns.

By way of example, use concat when combining rows from multiple tables or files, or combining (for eg) sales and budgets into a single fact table.

An example of a join would be adding lookup information, such as adding in a customer name to a source that contains the customer ID.

Hope that helps

Jonathan

(These are simple examples. Strictly speaking, outer joins can result in more rows and joins can also cause a source row to be replicated if the join condition is not unique).