Sum of items expression not working

[derbast]

Hello

I have 2 databases, one projects and one weekly report.
Now I want to count the number of parts from the weekly reports in the weekly report table according to the projects and display them in the project.

Database 1 Projects
Row | Project name | Part1 | Part 2 | Part 3
                  Text            Ref         Ref   | Ref
Database 2 Weekly Reports
Row | Comment | Project Name         | Part 1 | Part 2 | Part 3
          Text            Ref to Project Name  #              #        #

I made a Virtual Column with the Following expression for Database 1

SUM(
SELECT(
Database2[Part 1],
([Project Name] = [_THISROW].[Project Name])
)
)

but it only shows the value 0

can anyone help me ?

[diogolupcosta]

If you wanna count you should use

COUNT(
SELECT(
Database2[Part 1],
([Project Name] = [_THISROW].[Project Name])
)
)

[Fernando_Lopez1]

If database 1 is related to database 2 this must work:
SUM([Related Weekly Reports][Part 1])