表A1
id A
1 1
2 2
3 3

表A2
id B
2 22
3 33
5 55

表A3
id C
1 111
2 222
7 777

表A4
id D
5 5555
6 6666
7 7777

现在要写个查询，结果为，怎么写呢
id A B C D
1 1 0 111 0
2 2 22 222 0
3 3 33 0 0
5 0 55 0 5555
6 0 0 0 6666
7 0 0 777 7777

select a5.id,COALESCE(a1.\"A\",0) as A,COALESCE(a2.\"B\",0) as b,
COALESCE(a3.\"C\",0) as c,COALESCE(a4.\"D\",0) as d from
(select distinct id as id from (select id from a1 union
select id from a2 union select id from a3
union select id from a4)as a6) as a5 left join a1 _disibledevent= a4.id