Question

嗨，我想知道这在T-SQL中是否可行。

如果第2行和第3行/第5行和第6行的组合存在，那么想法是“不”返回第1行和第4行等行。

declare @table table
(
 A int,
 B char(2),
 C char(2),
 D char(2)
)

insert into @table
select 2, 'A1', 'B1', NULL  -- row 1
union
select 2, 'A1', 'B1', 'C1'  -- row 2 and row 3 is a combination (values are equal) 
union                       
select 3, 'A1', 'B1', 'C1'   
union
select 2, 'A2', 'B2', NULL  -- row 4
union
select 2, 'A2', 'B2', 'C2'  -- row 5 and row 6 is a combination (values are equal) 
union                     
select 3, 'A2', 'B2', 'C2'

任何想要参加此活动的人？谢谢最好的祝福史蒂夫

Answer 1

试试这个

SELECT DISTINCT A,B,C,D FROM @table 
WHERE 
A IS NOT NULL AND 
B IS NOT NULL AND 
C IS NOT NULL AND 
D IS NOT NULL

OR

SELECT DISTINCT A,B,C,D FROM @table 
WHERE 
D IS NOT NULL

Answer 2

这样的事情？

declare @table table
(
 ID INT ,
 A int,
 B char(2),
 C char(2),
 D char(2)
)

insert into @table
select 1, 2, 'A1', 'B1', NULL  -- row 1
union
select 2, 2, 'A1', 'B1', 'C1'  -- row 2 and row 3 is a combination (values are equal) 
union                       
select 3, 3, 'A1', 'B1', 'C1'   
union
select 4, 2, 'A2', 'B2', NULL  -- row 4
union
select 5, 2, 'A2', 'B2', 'C2'  -- row 5 and row 6 is a combination (values are equal) 
union                     
select 6, 3, 'A2', 'B2', 'C2'

SELECT *
FROM @table t
WHERE EXISTS(SELECT * FROM @table t1 WHERE t.id IN (t1.id + 1, t1.id + 2) 
      AND t.d IS NULL )

Answer 3

NOT EXISTS是要走的路：

SELECT A,B,C,D from @table t1
WHERE NOT EXISTS(
    SELECT 1 FROM @table t2
    WHERE t1.A < t2.A 
    AND COALESCE(t1.B,'')=COALESCE(t2.B,'') 
    AND COALESCE(t1.C,'')=COALESCE(t2.C,'') 
    AND COALESCE(t1.D,'')=COALESCE(t2.D,'') 
)

Demo

COALESCE - 技巧是比较两个空值。否则null=null将返回null，并且将包含具有空值的相等行。

Answer 4

我认为我们可以通过使用表的聚合和排序单独过滤记录来实现这一点。我相信，你想要消除那些后面跟行组合的行...... 如果是这样，下面可能会有效...

declare @table table
(
 A int,
 B char(2),
 C char(2),
 D char(2)
)

insert into @table
select 2, 'A1', 'B1', NULL  -- row 1
union
select 2, 'A1', 'B1', 'C1'  -- row 2 and row 3 is a combination (values are equal) 
union                       
select 3, 'A1', 'B1', 'C1'   
union
select 2, 'A2', 'B2', NULL  -- row 4
union
select 2, 'A2', 'B2', 'C2'  -- row 5 and row 6 is a combination (values are equal) 
union                     
select 3, 'A2', 'B2', 'C2'   


SELECT 
T.* 
FROM 
@table T
INNER JOIN 
(
    SELECT 
    T1.* 
    FROM
    (
        SELECT 
        ROW_NUMBER() OVER(ORDER BY B,C,D) As RowNumber, 
        MIN(A) AS A,
        B,
        C,
        D,
        COUNT(1) Cnt 
        FROM @TABLE
        GROUP BY B,C,D
    ) T1
    LEFT JOIN
    (
        SELECT 
        ROW_NUMBER() OVER(ORDER BY B,C,D) As RowNumber, 
        MIN(A) AS A,
        B,
        C,
        D,
        COUNT(1) Cnt 
        FROM @TABLE
        GROUP BY B,C,D
    ) T2 ON T2.RowNumber = T1.RowNumber + 1
    WHERE ISNULL(T2.Cnt,0) <= 1
) NonPostDuplicateRows
ON T.B = NonPostDuplicateRows.B
AND T.C = NonPostDuplicateRows.C
AND T.D = NonPostDuplicateRows.D

基于行的组合返回结果

4 个答案: