SQL Server 2017

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create table test (Column1    varchar(50), Column2 int);
 insert into test values('A',  200);
 insert into test values('A',  200);
 insert into test values('A',  0);
 insert into test values('B',  300);
 insert into test values('B',  200);
 insert into test values('C',  100);
 insert into test values('D',  0);
7 rows affected

select column1
     , SUM(column2) column2
     , COUNT(case when column2 = 0 then 1 end) total_zero
     , count(1) total
from test
group by column1


column1
column2
total_zero
total


A
400
1
3

B
500
0
2

C
100
0
1

D
0
1
1


Warning: Null value is eliminated by an aggregate or other SET operation.


SELECT t.column1
     , t.column2 / (CASE WHEN (t.total - t.total_zero) = 0 THEN 1 ELSE (t.total - t.total_zero) END)
FROM (SELECT column1
           , SUM(column2) column2
           , COUNT(CASE WHEN column2 = 0 THEN 1 END) total_zero
           , COUNT(1) total
      FROM test
      GROUP BY column1) t


column1
(No column name)


A
200

B
250

C
100

D
0


Warning: Null value is eliminated by an aggregate or other SET operation.