0 Replies Latest reply: Jan 31, 2018 10:06 AM by Jason Turner RSS

    How does Qlik auto define which table to use for a field?

    Jason Turner

      Hello all,

       

      possibly silly question here, however hopefully will make sense. If i have a table with 500 or so records, all with a uniqueID field

       

      example:

       

      Data:

       

      UniqueIDQ1Q2Q3
      1YesRed15
      2YesRed16
      3NoBlue18
      4YesGreen19

       

       

      and I then have an offshoot table which uses the UniqueID to pull through the answers to each seperate question, and a description, for example:

       

      Offshoot:

      Load UniqueID as UniqueID,

      Q1 as Question

      'Description' as Description

      resident data;


      concatenate(Offshoot)


      Load UniqueID as UniqueID,

      Q2 as Question

      'Description' as Description

      resident data;


      etc.

       

      I then have 500 unique ID's but in this offshoot table I will have 1500 of rows in the Offshoot table.

       

      When I go into sheets and do a simple KPI it recognises count(UniqueID) as 500  - and same with distinct before - I am just wondering how Qlik automatically picks which table a joining field comes from (in this case the data table, not the offshoot), whether there is science behind you pick the bigger table or what Qlik perceives as the source table, or whether it is dependant on what other visualisations are present?

       

      I have since fixed the join by doing a duplicate of the uniqueID as something else, then joining on that field, but just curious as to how the engine works?