查询获取一对多和多对一员工项目关系

Question

我有以下 table:

Table:

create table emp_project_mapping 
(
    emp_id varchar(10),
    pro_id varchar(10)
)

记录：

insert into emp_project_mapping values('E101','P1'),
                                      ('E101','P2'),
                                      ('E102','P1'),
                                      ('E103','P3'),
                                      ('E104','P3'),
                                      ('E105','P4');

查询 1：查找从事多个项目的员工。

预期结果：

emp_id  pro_id
--------------
E101    P1
E101    P2

查询 2：查找从事同一项目的不止一名员工。

emp_id  pro_id
--------------
E103    P3
E104    P3  
E101    P1
E102    P1

尝试:

查询 1：

;WITH CTE
AS
(
    SELECT  emp_id,
            pro_id,
            DENSE_RANK() over(order by emp_id) empid_rank,
            DENSE_RANK() over(order by pro_id) proid_rank
    FROM emp_project_mapping
)
SELECT emp_id,pro_id
FROM CTE
WHERE empid_rank = 1 and proid_rank>1

输出：

emp_id  pro_id
---------------
E101    P2

查询 2：

;WITH CTE
AS
(
    SELECT  emp_id,
            pro_id,
            DENSE_RANK() over(order by emp_id) empid_rank,
            DENSE_RANK() over(order by pro_id) proid_rank
    FROM emp_project_mapping
)
SELECT emp_id,pro_id
FROM CTE
WHERE empid_rank > 1 and proid_rank = 1

输出：

emp_id  pro_id
----------------
E102    P1

Answer 1

你可以试试这个....

对于第一个解决方案

        ;WITH CTE
        AS
        (
            SELECT  emp_id,
                    pro_id,
                    ROW_NUMBER() OVER (PARTITION BY emp_id ORDER BY pro_id) empid_rank
            FROM emp_project_mapping
        )
        SELECT * from emp_project_mapping WHERE emp_id IN (SELECT emp_id
        FROM CTE
        WHERE empid_rank > 1 )

第二种解决方案

        ;WITH CTE
        AS
        (
            SELECT  emp_id,
                    pro_id,
                    ROW_NUMBER() OVER (PARTITION BY pro_id ORDER BY emp_id) proid_rank
            FROM emp_project_mapping
        )
        SELECT * FROM emp_project_mapping WHERE pro_id IN (SELECT pro_id 
        FROM CTE 
        WHERE proid_rank>1)

查询获取一对多和多对一员工项目关系

Query to get one to many and many to one employee project relationship

sql-server

sql-server-2008-r2