Splitting values where keys matching

hi, Sergei8000 

try below

Column 1= 
 var a = CALCULATE(SUM('Table 2'[Col1]))
 var b = CALCULATE(COUNT('Table 1'[id]))
  return
  DIVIDE(a,b)

repeat for all column

Hi Sergei8000 ,

According to your description, here are my steps you can follow as a solution.

(1) My test data is the same as yours.

(2) We can create calculated columns.

Col 1 = 
 var a = CALCULATE(SUM('Table 2'[Col1]),FILTER('Table 2','Table 2'[unique_id]=EARLIER('Table 1'[id])))
 var b = COUNTROWS(FILTER('Table 1','Table 1'[id]=EARLIER('Table 1'[id])))
  return
  DIVIDE(a,b)

Col 2 = 
 var a = CALCULATE(SUM('Table 2'[Col2]),FILTER('Table 2','Table 2'[unique_id]=EARLIER('Table 1'[id])))
 var b = COUNTROWS(FILTER('Table 1','Table 1'[id]=EARLIER('Table 1'[id])))
  return
  DIVIDE(a,b)

Col 3 = 
 var a = CALCULATE(SUM('Table 2'[Col3]),FILTER('Table 2','Table 2'[unique_id]=EARLIER('Table 1'[id])))
 var b = COUNTROWS(FILTER('Table 1','Table 1'[id]=EARLIER('Table 1'[id])))
  return
  DIVIDE(a,b)

(3) Then the result is as follows.

Best Regards,

Neeko Tang

If this post  helps, then please consider Accept it as the solution  to help the other members find it more quickly.