删除满足一个条件的所有记录

Question

我有一个 table 如下所示：

ID	section	Yes_no
EE_1	sec_21	Y
EE_1	sec_23	N
EE_1	sec_22	N
EE_2	sec_21	N

我正在寻找一种方法 return 只有在“Yes_no”列中没有 'Y' 的 ID。所需输出如下：

ID	section	Yes_no
EE_2	sec_21	N

Answer 1

Select * from table_X where ID not in (Select ID from table_X where Yes_no ='Y')

Running example

Answer 2

我想这就是你想要的：

create table MyTable(
  ID varchar(10),
  section varchar(50),
  Yes_no varchar(1)
)
insert into MyTable values 
('EE_1','sec_21','Y'),
('EE_1','sec_23','N'),
('EE_1','sec_22','N'),
('EE_2','sec_21','N')

select *
from MyTable t1
where t1.Yes_no = 'N' and not exists
(select * from MyTable t2 where t2.ID = t1.ID and t2.Yes_no = 'Y')

DBFiddler: https://dbfiddle.uk/?rdbms=sqlserver_2019&fiddle=0b24198e227588df323c579facd37153

Answer 3

Window 对于这种事情，函数通常是最快的

SELECT
  t.ID,
  t.section,
  t.Yes_no
FROM (
    SELECT *,
      CountY = COUNT(CASE WHEN t.Yes_no = 'Y' THEN 1 END) OVER (PARTITION BY t.ID)
    FROM YourTable t
) t
WHERE CountY = 0;

db<>fiddle

Answer 4

您可以使用 exists 关键字来执行此查询，因为 exists 的性能优于 in。

select *
from Table t
where t.Yes_no = 'N' and not exists
(select * from Table b where b.ID = b.ID and b.Yes_no = 'Y')

删除满足一个条件的所有记录

Removing all records where one condition is met

sql

sql-server

conditional-statements