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Thread: UNION/INTERSECTION/MINUS in Kettle

  1. #1

    Default UNION/INTERSECTION/MINUS in Kettle

    Hi,
    I was wondering if Kettle has some specific operators for regular SQL UNION/INTERSECTION/MINUS operations.
    If not, can I instead use "ExecSQL"?

    Also, is there somewhere a general form of ktr and kjb XML schemas (something like DTD or XSD).

    Thanks.

  2. #2
    Join Date
    Nov 1999
    Posts
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    Default

    Obviously you can use any SQL that your database supports in a step like "Table Input" and get the result.
    For other data sources we also have a few things...

    You can do a UNION by directing the output of 2 (or more) steps to any other step. The same rules apply as with SQL: the rows have to be of the same layout. (data types, etc)
    To determine the differences between 2 data streams we have a powerful "Merge Rows (diff)" step that works wonders.

  3. #3

    Default

    Thanks very much for this reply, it helps a lot.
    By the way, can I use Merge Rows for all three operators> I was thinking just after the Merge rows step to add Filter step and filter rows according to the flag field.
    - If it is UNION, then without any filter (All rows should be at the output) - Does it make duplicates?
    - If it is INTERSECTION, that I keep only those with flag field equals to 'identical'
    - If it is MINUS, then I keep those with the flag field 'new' or 'changed'.

    What do you think, is this the good choice?

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