mysql - mysql : 3 个或更多 SELECT 的结果之间的交集

Question

好的，假设我们有 3 个或更多，比如说“k”个具有相同结构的表：
表 1：

id customer_id
1  35
2  36
3  37

表2：

id customer_id
1  35
2  38
3  39

...
表k：

id customer_id
1  35
2  69
3  52

我如何选择所有表中存在的所有 customer_id（换句话说：交叉点），在这个例子中，如果有 3 个表，结果应该是这样的

id customer_id
1  35

如果有人可以提供帮助，我将不胜感激

Answer 1

create table dela (
    id int
);
create table delb (
    id int
);
create table delc (
    id int
);

drop table dela;

insert into dela values (1),(2),(3);
insert into delb values (5),(4),(3);
insert into delc values (5),(1),(3);

select 
    a.id
from
    dela a
        join
    delb b ON a.id = b.id
        join
    delc c ON a.id = c.id;

Answer 2

SELECT t1.customer_id
FROM `table 1` AS t1
INNER JOIN `table 2` AS t2 ON t1.customer_id = t2.customer_id
-- ...
INNER JOIN `table k` AS tk ON t1.customer_id = tk.customer_id

Answer 3

尝试这个 ：

SELECT 
    customer_id
FROM (
    SELECT
        customer_id
        1 as counter 
    FROM 
        table1

    UNION ALL 

    SELECT
        customer_id
        1 as counter 
    FROM 
        table2

    ....

    SELECT
        customer_id
        1 as counter 
    FROM 
        tablek

) as tmp
GROUP BY
    customer_id
HAVING
    SUM(counter) = k

Answer 4

这应该有效：

SELECT table1.id, table1.customer_id
FROM table1, table2, ..., tableK
WHERE table1.id=table2.id
AND table1.id=table3.id
...
AND table1.id=tableK.id

为简单起见，您还可以为每个表定义别名：

FROM table1 a, table2 b, ..., tableK k
WHERE a.id=b.id