Support for flow variables in date/time type


I read in Wrapped Metanode Cannot Parse Date Flow Variable - #6 by Iris that flow variables do not support date/time type. Maybe this information is outdated, but in my experience with the matter is along the lines. I actually am a bit puzzled that the support is missing for two things.

  • The variable expression node half suggest support. One can use a function to convert string to variable, but cannot select date type as type for the output variable.

  • I feel that filtering by date is a common task.

In my last workflow, I failed to make it work.

For the time being, I will have to convert stuff to and fro. You can find my attempt at US polling places – KNIME Community Hub

I would appreciate, if the date/time type would be supported by flow variables in the future.

Kind regards


Hi @Thiemo.Kellner,

You can pass dates as string flow variables and use them in the node’s settings.
Also, for date/time row filtering, we have also the Date&Time-based Row Filter node.

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Hi @armingrudd

I did not see the data&time-based row filter node. Thanks for nudging me at it.

The direct use of the date string in the ordinary Row Filter with range is prevented by the hyphens, making them an impossible integer. Be it as it may, your suggestion works perfectly.

Yes, the range filter is for numeric columns. For date and time range filter you can use the Date&Time-based Row Filter.

The range filter will in fact work with Strings too, (so you could filter where a String column is between “Cat” and “Elephant” for example (eg Dog is, but Zebra isn’t :wink:), but sadly in this case it complains about comparing a Date to a String.

In some other nodes, (Rule Engine and Rule Based Row Filter/Splitter ?) comparing dates and Strings in “yyyy-MM-dd” format is perfectly allowed and even required, so it is just one of those inconsistencies that is there to keep us all on our toes! :grin:

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Dear @takbb,

You are right, it is possible to use range for strings. I’ve never used the range for strings since I saw the warning which says it may not work as expected and I’m very cautious. I usually rely on regex for strings.

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