我现在有三张表a,b,c 其中a.id=b.parent_id, b.id=c.parent_id, 有没有办法弄成像d表的样式呢?
a:
id1 字段1 字段2
1 aa bb
b:
id parent_id 字段3
2 1 cc
3 1 dd
c:
id parent_id 字段4
4 2 ee
5 2 ff
6 3 ggd:
id 字段1 字段2 id Parent_id 字段3 id parent_id 字段4
1 aa bb 2 1 cc 4 2 ee
null null null null null null 5 2 ff
null null null 3 1 dd 6 3 gg方便于asp时读取,谢谢!
a:
id1 字段1 字段2
1 aa bb
b:
id parent_id 字段3
2 1 cc
3 1 dd
c:
id parent_id 字段4
4 2 ee
5 2 ff
6 3 ggd:
id 字段1 字段2 id Parent_id 字段3 id parent_id 字段4
1 aa bb 2 1 cc 4 2 ee
null null null null null null 5 2 ff
null null null 3 1 dd 6 3 gg方便于asp时读取,谢谢!
case when b.id=(select min(id) from b where parent_id=b.id then a.字段1 else null end ) as a_字段1,
case when b.id=(select min(id) from b where parent_id=b.id then a.字段2 else null end ) a_字段2,
case when c.id=(select min(id) from c where parent_id=c.id then b.id else null end ) as b_id,
case when c.id=(select min(id) from c where parent_id=c.id then b.Parent_id else null end ) as b_Parent_id,
case when c.id=(select min(id) from c where parent_id=c.id then b.字段3 else null end )b_字段3,
c.id,
c.parent_id,
c.字段4
from b
left join a on b.parent_id = a.id
right join c on b.id = c.parent_id