无法更新视图或函数'cte'，因为它包含集合，或者DISTINCT或GROUP BY子句，或者PIVOT或UNPIVOT运算符

Question

我想要使用Having by来删除。

所以我尽量执行以下语句：

;WITH cte As 
(
select emp_num, [from_date],[to_date],[ req_ser], [ req_year] 
from empmission 
group by emp_num, [from_date],[to_date],[ req_ser], [ req_year] 
having count(*) >2 
) 

DELETE 
FROM cte 

，但我得到以下异常：

无法更新视图或函数“CTE”，因为它包含 聚集，或DISTINCT或GROUP BY子句，或者PIVOT或UNPIVOT运算符。

Answer 1

使用窗口功能：

WITH todelete As (
     select em.*, 
      row_number() over (partition by emp_num, [from_date],[to_date],[ req_ser], [ req_year] 
           order by (select null)) as cnt 
     from empmission em 
) 

DELETE FROM todelete 
WHERE cnt > 2; 

注意，这将删除所有行有重复的值。通常情况下，你想保留其中的一个值。如果是这样，请提出另一个问题。

Answer 2

内部连接回到原始表并删除它。

;WITH cte As 
(
select emp_num, [from_date],[to_date],[ req_ser], [ req_year] 
from  empmission 
group by emp_num, [from_date],[to_date],[ req_ser], [ req_year] 
having count(*) >2 
)  
DELETE E 
FROM cte C 
JOIN empmission E ON C.emp_num = E.emp_num 
         AND C.from_date = E.from_date 
         AND C.to_date = E.to_date 
         AND C.req_ser = E.req_ser 
         AND C.req_year = E.req_year 

Answer 3

的另一种方式，跳过CTE，做EXISTS代替：

delete from empmission e1 
where exists (select 1 
       from empmission e2 
       where e1.emp_num = e1.emp_num 
       and e1.[from_date] = e2.[from_date] 
       and e1.[to_date] = e2.[to_date] 
       and e1.[ req_ser] = e2.[ req_ser] 
       and e1.[ req_year] = e2.[ req_year] 
       group by emp_num, [from_date],[to_date],[ req_ser], [ req_year] 
       having count(*) > 2)