vLookups in Knime

KNIME Analytics Platform
1

Hi, I'm just beginning to learn about how things work in Knime, and it looks very promising.

I'm trying to create a vLookup functionality, but it's proving to be more difficult.

I currently have one "database reader" for each table in my mysql database that I want to link to. Then for each "database reader", I have a "rowID" which changes the _

_id_ column into the "row_id". I have a file reader with my data file.

I am trying to use a Joiner, but I cannot specify a column in the first table to "join ____ on ()" (like in SQL)

Can anybody give me a tip? Thanks in advance for your help!

2

sgalal wrote:
I am trying to use a Joiner, but I cannot specify a column in the first table to "join ____ on ()" (like in SQL)

You either have to switch the two inputs or put the join column into the row key of the first table (which may not be possible in all cases, though).

Thorsten

3

thor wrote:
You either have to switch the two inputs or put the join column into the row key of the first table (which may not be possible in all cases, though).

Thanks! What I can do is create N views for the N columns I want to look up. Then do the joins, and finally put all the columns together in a new table.

4

Hi,

Are they "N views" from the same underlying table of data or is it multiple different tables?

Jay

5

Jay wrote:
Hi,

Are they "N views" from the same underlying table of data or is it multiple different tables?

Jay

Hi Jay,

It's the same data. One Table, N-columns which I want to "v-lookup" -)

6

Hi,

Sorry I amst guessing here. Are you trying to accomplish something like a "pivot" i.e. a reshaping of the data to turn multiple rows into a single row?

A VLOOKUP() is the Microsoft functionality I think? So you want to return a reference value for the first match of your key? If you use a join you need to have a table with only distinct values.

Ifyou could show a small example (only a few lines) of the input table and the desired end output table we might be able provide more options?

Best regards,

Jay