topic Doubt in concatenate in App Development

Doubt in concatenate

Thu, 14 Jul 2016 08:15:45 GMT

Hi, Sorry for the basic question but this is not working:

FactTable:

Load A,B,C;

SELECT ... FROM Table1;

CONCATENATE (FactTable)

Load A,B;

SELECT ... FROM Table2;

LEFT JOIN

LOAD A,C;

SELECT ... FROM SubTable;

The LEFT join is workinf fine, if I run it alone Table2 and Subtable, column C is fine.

So I was expecting Field C from Subtable to concatenate on FactTable,it returns NULL

Any tip on what am I doing wrong?

Thanks

Re: Doubt in concatenate

swuehl — Thu, 14 Jul 2016 18:27:32 GMT

Try doing the JOIN of your tables Table2 and SubTable in your SQL SELECT part (single LOAD statement so to say).

Re: Doubt in concatenate

Anonymous — Thu, 14 Jul 2016 19:14:56 GMT

I think I know why it doesn't work...

FactTable:
Load A,B,C;
SELECT ... FROM Table1;

CONCATENATE (FactTable)
Load A,B;
SELECT ... FROM Table2;

--> result is a table with Fields A,B,C, even if some C - Fields are null().

LEFT JOIN
LOAD A,C;
SELECT ... FROM SubTable;

will only work, if A and C match --> Synthetic Key!!!

--> solution could be the following:


FactTable:
Load A,B;
SELECT ... FROM Table2;
LEFT JOIN
LOAD A,C;
SELECT ... FROM SubTable;
CONCATENATE (FactTable)
Load A,B,C;
SELECT ... FROM Table1;

--> first join (only A as Key), then concatenate the rest.

You could even remove

CONCATENATE (FactTable)

because if all names are the same, QlikView will do an implicit concatenate.