SQL服务器：只提取满足特定条件的记录

Question

我在 SQL 服务器中有两个 table，如下所示：

[table - 一个]

cod	name
1	aaa
2	bbb
3	ccc
4	ddd
5	eee
6	fff
7	ggg
8	hhh

[table - b]

cod	location	auth
1	1001	1
2	1002	0
3	1003	null
4	1002	1
4	1003	1
5	1001	0
5	1003	null
6	1002	0
6	1001	0
7	1003	1
7	1002	null
8	1001	1
8	1003	0

我加入上面两个table提取记录，但是我只想显示满足下面条件的记录

如果code对应的位置只有一个

如果 auth 不是'1'则无条件提取

如果代码对应的位置有多个

提取其中有两个或多个auth为'1'的代码。
提取只有一个 auth 等于 '1' 但 null 存在的代码
在没有任何 auth 等于'1'的情况下提取代码。

结果应如下所示：

cod	name	location	auth
2	bbb	1002	0
3	ccc	1003	null
4	ddd	1002	1
4	ddd	1003	1
5	eee	1001	0
5	eee	1003	null
6	fff	1002	0
6	fff	1001	0
7	ggg	1003	1
7	ggg	1002	null

我的查询现在在下面。

WITH T AS 
(
    SELECT 
        a.cod, b.location, b.auth,
        ROW_NUMBER() OVER(PARTITION BY a.cod ORDER BY b.location) COL
    FROM 
        a 
    LEFT JOIN 
        b ON a.cod = b.cod
    GROUP BY 
        a.cod, b.location, b.auth
) 
SELECT DISTINCT(cod), location, auth, COL, CHK 
FROM (SELECT T.cod, T.location, T.auth, T.COL,
CASE WHEN MAX(T.COL) OVER(PARTITION BY T.cod)=1 AND T.auth=1 THEN 'S-AUTH'
     WHEN MAX(T.COL) OVER(PARTITION BY T.cod)=1 AND T.auth=0 THEN 'S-NONE'
     WHEN MAX(T.COL) OVER(PARTITION BY T.cod)=1 AND T.auth IS NULL THEN 'S-DEFAULT'
     WHEN MAX(T.COL) OVER(PARTITION BY T.cod)<>1 AND T.auth=1 THEN 'M-AUTH'
     WHEN MAX(T.COL) OVER(PARTITION BY T.cod)<>1 AND T.auth=0 THEN 'M-NONE'
     WHEN MAX(T.COL) OVER(PARTITION BY T.cod)<>1 AND T.auth IS NULL THEN 'M-DEFAULT'
     ELSE 'N'
     END AS CHK
 FROM T) A   
 ORDER BY cod ASC

请指教和帮助。

Answer 1

如果您想要上面提到的输出，请使用以下查询

with t as
         (
             select a.cod, a.name, b.location, b.auth,
                    sum(b.auth) over (partition by b.cod) as AuthSum,
                    max(case when b.auth is null then 1 else 0 end) over (partition by b.cod) as ContainsNull
             from a
             join b ON a.cod = b.cod
         )
select cod, name, location, auth
from t
where (AuthSum >= 2) --Extract the code where there are two or more of which auth is '1'.
    OR (AuthSum = 1 and ContainsNull = 1) --Extract the code where there is only one auth equal to '1' but null exists
    OR (AuthSum is null or AuthSum = 0)  --Extract unconditionally if auth is not '1' OR Extract the code without any auth equal to '1'

SQL服务器：只提取满足特定条件的记录

SQL Server : extract only records that meet specific conditions

sql-server