SQL查询获得预期结果

Question

这是我的数据库架构

Table_A
-id 
-status

Table_B
-id

Table_A_has_B
-id
-id_A
-id_B

我需要从Table_B中选择所有记录，其中所有关联的Table_A记录的status=1均为status=1 ，如果Table_B记录没有任何关联的Table_A，则也应选择。

测试用例：

CREATE TABLE table_a (id int(2),status int(1));
INSERT INTO table_a (id, status)
VALUES (1,1),(2,0),(3,1),(4,1),(5,1);

CREATE TABLE table_b (id int(2));
INSERT INTO table_b (id) VALUES (1),(2),(3),(4);

CREATE TABLE table_a_has_b (id int(2),id_A int(2),id_B int(2));
INSERT INTO table_a_has_b (id, id_A, id_B)
VALUES(1, 1, 1),(2, 2, 1),(3, 3, 1),(4, 4, 2),(5, 5, 2),(6, 3, 4),(7, 4, 4);

查询应选择：

+----+
|b.id|
+----+
|   2|
|   3|
|   4|
+----+

• 不应选择ID 1，因为其table_a记录之一的状态为= 0
• 应该选择ID 2和ID 4，因为其所有table_a记录的状态均为= 1
• 应该选择ID 3，因为没有关联的table_a记录，对于同一标准的另一种观点是：应该选择ID 3，因为没有任何table_a记录，其中status = 0

Answer 1

编辑答案-

select b.* from table_B b 
left outer join table_A_has_B ab on ab.id_B = b.id
where ab.id in (
    select id from table_A_has_B ab
    where (id_A in (select id from table_A where status = 1 ))
)
or b.id not in 
(select id_B from table_A_Has_B )

旧答案-

select b.* from table_B b
left outer join table_A a on b.id = a.id
where a.status = 1 or a.id is null

Answer 2

Select ...
From Table_B As B
    Left Join   (
                Select AB.id_B, A.id, A.status
                From Table_A_has_B As AB
                    Join Table_A As A
                        On A.id = AB.id_A
                Where A.status = 1
                ) As Z
        On Z.id_B = B.id

原始帖子的这一部分内容不清楚： if a Table_B record hasn't any associated Table_A also should be selected. 。

如果只需要来自Table_B的行，则：

Select B.*
From Table_B As B
Where Exists    (
                Select 1
                From Table_A_has_B As AB
                    Join Table_A As A
                        On A.id = AB.id_A
                Where A.status = 1
                    And AB.id_B = B.id
                )

如果要从Table_ B行，或者给定id_B Table_A_has_B中没有行，或者必须将行与status为1的Table_A项目相关联，则：

Select B.*
From Table_B As B
Where Exists    (
                Select 1
                From Table_A_has_B As AB
                    Join Table_A As A
                        On A.id = AB.id_A
                Where A.status = 1
                    And AB.id_B = B.id
                )
    Or Not Exists   (
                    Select 1
                    From Table_A_has_B As AB
                    Where AB.id_B = B.id
                    )

如果您要的是Table_A中的行，但仅状态为1的行，而对于所有其他行，则为空，那么我提供的第一个查询就是解决方案。 为我们提供一些预期的输出结果显然会极大地帮助您。

编辑给定的OP更新

有了您的更新（现在只能使您清楚地知道要实现的目标），您可以执行以下操作：

Select B.id
From Table_B As B
Where Not Exists    (
                    Select 1
                    From Table_A_has_B As AB
                        Join Table_A As A
                            On A.id = AB.id_A
                    Where A.status <> 1
                        And AB.id_B = B.id
                    )

Answer 3

通过改写您的需求语句以选择不具有状态<> 1关联的table_A的table_B，我进入以下查询语句：

select distinct b.* 
from table_B b
left outer join table_A_has_B ab on ab.id_B = b.id
left outer join table_A a on a.id = ab.id_A and a.status <> 1
where a.id is null

要么

select b.* 
from table_B b
where not exists (select null from table_A_has_B ab 
inner join table_A a on a.id = ab.id_A and a.status <> 1
where ab.id_B = b.id)