How to sum three columns in qlickview (two from table1 and one from table2)

Question

I need to create a 4th column in either table as a sum of columns 1,2 and 3. How can I do it?.

LOAD column1, 
     KeyColumn 
FROM
[C:\Qlik\file1.xlsx]
 (ooxml, embedded labels, table is sheet1);

LOAD column2, 
     column3, 
     KeyColumn 
FROM
[C:\Qlik\file1.xlsx]
(ooxml, embedded labels, table is sheet2);

Answer 1

I changed your LOAD script into a INLINE version, so it is not depending on external files and other users can copy and paste it easy.

My LOAD script:

Data:
LOAD * INLINE [
column1, KeyColumn
1, Product_A
2, Product_B
3, Product_C
];

OUTER JOIN
LOAD * INLINE [
column2, column3, KeyColumn
10, 100, Product_A
20, 200, Product_B
30, 300, Product_C
];

I use the outer join to be sure that all values for KeyColumn are in the resulting table.

In the dashboard I load all available columns and get:

Next step is to iterate over the existing values and add the three columns and store them in column4.

LOAD  
Num#(column1 ,'##.###') + Num#(column2 ,'##.###') + Num#(column3 ,'##.###') as column4
Resident Data;

Attention. This

column1 + column2 + column3  as column4

will not work!

After adding the new column to the dashboard you get:

I hope thats what you were asking for.

Update after comments.

In your case

Data:
LOAD column1, 
     KeyColumn 
FROM
[C:\Qlik\file1.xlsx]
 (ooxml, embedded labels, table is sheet1);

OUTER JOIN 
LOAD column2, 
     column3, 
     KeyColumn 
FROM
[C:\Qlik\file1.xlsx]
(ooxml, embedded labels, table is sheet2);

LOAD  
Num#(column1 ,'##.###') + Num#(column2 ,'##.###') + Num#(column3 ,'##.###') as column4
Resident Data;

should work.