sum a column value based on another table column

[Anonymous]

I have a table1 with 2 columns A & B which has value like below 

A	B
p1	1
p1	3
p2	4
p7	6

Another table 2 with column A

A

p2

p3

p6

p8

p10

Both the tables are connected via dimension table table3 (union of table1 & Table2 )which looks like 

A

p1

p2

p3

p6

p7

p8

p10

p12

I wanted to sum the column B of table1 where column A of table1 is not matching with Column A of table 2 .

Desired O/P : (1+3+6)=10

I am using calculate with Filter using Values but not getting correct output .

[amitchandak]

@Anonymous , Try a measure like

measure=
var _tab = except(allselected(Table1[A]),allselected(Table1[b]))
return
calculate(countrows(Table1), filter(Table1,Table1[A] in _tab))

[Anonymous]

Thanks for such a quick response , I made a little modification to make it work but the problem is it does not work properly when filter is applied 

[Anonymous · Accepted solution]

After modification it works . Thanks Amitchandak .

measure=
var _tab = except(selectcolumns(Table1,"col",Table1[A]),selectcolumns(Table2,"col",Table2[a]))
return
calculate(sum(Table1[b], filter(Table1,Table1[A] in _tab))