CODEWITHSUNDEEP
kettlepentaho-data-integrationpdi
Rio Odestila
Rio Odestila

Reputation: 125

Applying Left Join in Pentaho

I'm try to create Transformation and need to merge two Database based on query like that by using Merge Join and I little bit confuse what should i filled in First Step, Second Step to Lookup for that each query format.

Query Format :

SELECT * FROM A a LEFT JOIN B b on a.value=b.value

SELECT * FROM A a LEFT JOIN B b on b.value=a.value

Upvotes: 0

Views: 4611

Answers (2)

AlainD
AlainD

Reputation: 6356

There are various way to do it.

  • Write the sql with the join in the Table input step. Quick an dirty solution if your table are in the same database, but do not tell a PDI expert you did it that way.

  • If you know there is only one B record for each A record, use a Lookup Stream Step. Very, very, very efficient. The Main flow is the A and the lookup step is B.

  • If you have many B records for each A records, use a Join Rows. Don't be afraid, you do not really make a Cartesian product, as you can put your condition a.value=b.value.

  • In the same situation, you can also make a Merge join. The first step is the step you write fist in the sql select statement.

Upvotes: 1

Helping Hand..
Helping Hand..

Reputation: 2440

Multiple ways to do this. you can use TableInput Step and just simply write your query. No need to do anything else for implementing above query.

Upvotes: 1

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