DAX Summing Values in Another Table

I am new to DAX.

I have 2 tables. Let's call them Table_1 and Table_2.

Let's say they look like this:

Table_1

ID     Table_2_ID     Person
1      1              Steve
2      1              Steve 
3      1              Steve
4      2              John
5      2              John
6      3              Sally


Table_2     Sales
1           100
2           50
3           5

I want to return results that look something like this:

ID     Table_2_ID     Person     Sales
1      1              Steve      100
2      1              Steve      100
3      1              Steve      100
4      2              John       50
5      2              John       50
6      3              Sally      5

How can I return this with a Dax function?

I know I need to use LOOKUPVALUE and/or the RELATED function, in combination with SUM, but I'm not sure how.

I'm not looking to produce a table, but a measure that when I use it in combination with other columns in Power BI, it applies the appropriate amount to each person in Table_1.

Solution

This can be done either by a calculated column or by a measure.

CC in Table_1:

Sum_Tab2 = 
var t2_ID = [Table_2_ID]

return
CALCULATE(
    SUM('Tabel_2'[Sales]),
    'Tabel_2'[ID] = t2_ID
)

Measure:

SumTab2_measure = 

var currentT2ID = MAX('Tabel_1'[Table_2_ID])

return
CALCULATE(
    SUM('Tabel_2'[Sales]),
    'Tabel_2'[ID] = currentT2ID
)

No relationships needed. However, for the measure to work in a visual table the [Tabel_2_ID from Tabl_1 needs to be present with this solution.

These may have to be slightly altered depending on your other filter dependencies and such so that they behave as you want them to.