creating a dataflow

Hello I’m trying to create a data flow in KNIME, but I don’t want to create the tables I’m creating in the database, just in memory, how do I reference the tables that I have already created in memory? So basically I have 3 DB readers and want to use a query that selects from all of them (and joins)

Hey @hookemhorns,

Welcome to the KNIME Forum! You can do this in KNIME, there is no obligation to do the join in database:

If you’re talking about caching the data out of the 3 DB readers you can also do this. If you save the workflow with the DB Reader nodes in the executed state, the next time you run the workflow it will not query the database again.

Let me know if that makes sense.

Thanks and Gig 'Em :wink:
Wali Khan


Thanks @wkhan, I thought this may be the right answer, but my joins are a little bit different that what it’s giving me available.
This is what I want to do
left join table1 e on n.domain_name = e.domain_name and month(n.valid_till) = e.month_expiring_in_2020 and year(n.valid_till) = 2020
where e.domain_name is null
group by account_id
I don’t see where I can use month or year in my joins.

nevermind, I can just edit this in the table selector in the previous step. and then use that to join it on.

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@wkhan actually I was able to do most of this in the previous step, but I need some ideas on how to add the year(n.valid_till) = 2020, should I use a column_filter right after the joiner? Also just noticed the Aggie reference… nice! :smiley:


Hey @hookemhorns,

Glad you were able to figure a lot of it out. For the dates, look at the ‘Row Filter’ Node. You can specify the value of a column to filter on.

Wali Khan

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