Joining two Tables based on time stamps

Hello all. I would like some help here.
I would like to form a single Table from two Tables. Table 1 has three columns (time, temperature and humidity). Table 2 has two columns (time and flow rate). Both have a common column, i.e. time, which represents the time stamps for each row data. The time stamp values are not in synch. Table 1 has time stamps every minute, while Table 2 has time stamps every 3 minutes. I would like to combine both into one Table (Table 3), based on the time stamps for Table 2. In other words, Table 3 will have four columns namely time, temp, humidity, flow rate to represent temp, humidity and flow rate for the same time stamp.
How to do this in KNIME would be very helpful.

Hi @Oao -

As a first pass, I would convert the timestamps to a common format, perhaps using a String to Date&Time node. I’d then use a Joiner node to bring together the two tables on the converted time, and a Missing Value node to interpolate the flow rate as needed.

Does that help?

Hi @Oao

You can use a Joiner node, and perform a right outer join (top Input = Table 1, bottom input = Table 2).Screenshot%20from%202020-01-09%2022-05-26
gr. Hans

Hi @Oao,

Assuming for each table the timestamp is unique I suggest to solve it using a concatenate node followed by an groupby node.
See example.

Br Hermann

DEMO.knwf (11.4 KB)

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Thanks Morpheus. Worked well. I used 2 File Reader nodes + 1 Concatenate node + 1 GroupBy node. Worked perfectly.

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