Hi , @Tim24
Thanks for your response! This is my test data and the result:
ClearCollect(Table1Test , { 'Delta / Full FAI' : "DETLA" , Flag : "yes" }, { 'Delta / Full FAI' : "DETLA" , Flag : "yes" }, { 'Delta / Full FAI' : "DETLA" , Flag : "yes" }, { 'Delta / Full FAI' : "DETLA" , Flag : "yes" }, { 'Delta / Full FAI' : "DETLA" , Flag : "no" } , { 'Delta / Full FAI' : "FULL" , Flag : "yes" },{ 'Delta / Full FAI' : "FULL" , Flag : "no" } , { 'Delta / Full FAI' : "-" , Flag : "yes" },{ 'Delta / Full FAI' : "*" , Flag : "no" } )

My Combo box 1 -items: ["yes","no"]
I use this code in PieChart - items:
AddColumns( GroupBy(Table1Test , "Delta / Full FAI" , "DFF" ) , "TotalDFF" , CountIf( DFF ,Flag= ComboBox1.Selected.Value) , "DFF1" , Concatenate('Delta / Full FAI', " - ", CountIf( DFF ,Flag= ComboBox1.Selected.Value) ) )
If this reply can help you , you can click mark this reply as solution (Accept solution) which can help more people, thanks in advance!
Best Regards,
Yueyun Zhang