topic Re: How to use multiple join on tMap in Talend Studio

How to use multiple join on tMap

Anonymous — Wed, 10 Jul 2019 04:21:23 GMT

Hi,
I'd like to make a multiple condition join with a t Map. I have an input source data which contains 4 possibles values for a field.
I'd like to join the two when one of the main data match one of the lookup data.
In SQL that would be something like : left join table B ON (A.bar1=B.bar1 or A.bar1=B.bar2 or A.bar2=B.bar1 or A.bar2=B.bar2)
Thanks.

Re: How to use multiple join on tMap

yashfreaky — Wed, 10 Jul 2019 08:04:46 GMT

Hi Arun,

If you have 2 input sources - Main table and Look-up table which is connected to tMap,

You can find tMap settings at look-up table header in tMap - Join Model: Inner Join /Left Outer Join.

LEFT OUTER JOIN.JPG

Re: How to use multiple join on tMap

Anonymous — Wed, 10 Jul 2019 08:41:03 GMT

Hello,

Please also take a look at this community article about:https://community.talend.com/t5/Design-and-Development/tMap-expression-syntax/ta-p/21575

Best regards

Sabrina

Re: How to use multiple join on tMap

ThWabi — Thu, 25 Jul 2019 16:24:21 GMT

Hello arunviswa,

one possible solution I would like to offer is to create copies of your lookup data input component (B), so that you have 4 of them connected to the tMap. For each lookup, join the main input (A) using a different one of the conditions you mentioned in the SQL. Set the join model to "left outer join". In the "Var" section of the tMap, you can check which of the 4 lookups returned null or not null and proceed as needed.

Best regards,

Thomas