SQL Server 2019

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CREATE TABLE [OWNER](
    [personId] [int] NULL,
    [ownerId] [int] NULL,
    [firstName] [varchar](255) NULL,
    [lastName] [varchar](255) NULL,
);

CREATE TABLE [INCOME](
    [personId] [int] NULL,
    [amount] [float] NULL,
    [received] [date] NULL,
)
INSERT INTO OWNER Values(1,null,   'John', 'Smith')
INSERT INTO OWNER Values(1,null,   'John', 'Smith')
INSERT INTO OWNER Values(1,null,   'John', 'Smith')
INSERT INTO OWNER Values(200,1,    'Tom', 'Lawn')
INSERT INTO OWNER Values(3,3,      'Chris', 'Hanson')
INSERT INTO OWNER Values(400,4,    'Jack', 'Man')
INSERT INTO OWNER Values(4,null,   'Donald', 'McMan')
INSERT INTO OWNER Values(5,null,   'John', 'Hanson')
INSERT INTO OWNER Values(700,5,    'Peter', 'Darcy')
INSERT INTO OWNER Values(700,5,    'Peter', 'Darcy')


Insert INTO INCOME VALUES(1, 300, '2020-01-01')
Insert INTO INCOME VALUES(200, 1000, '2020-01-01')
Insert INTO INCOME VALUES(3, 200, '2020-01-01')
Insert INTO INCOME VALUES(4,300, '2020-01-01')
Insert INTO INCOME VALUES(5,300, '2020-01-01')
Insert INTO INCOME VALUES(1,300,  '2020-01-01')
Insert INTO INCOME VALUES(3,300,  '2020-01-01')
Insert INTO INCOME VALUES(5,500,  '2020-01-01')
Insert INTO INCOME VALUES(700,500,  '2020-01-01')
19 rows affected

select coalesce(o.ownerid, i.personid), 
       sum(amount) as total,
       count(*) as rows
from income i cross apply
     (select top (1) o.*
      from owner o
      where o.personid = i.personid
     ) o
group by coalesce(o.ownerid, i.personid)


(No column name)
total
rows


1
1600
3

3
500
2

4
300
1

5
1300
3