在表中查找重叠

Question

我在 SQL Server 中有一个存储地毯的表。每个都有自己的 ID，以及以米为单位（从到到）的范围和颜色。

CREATE TABLE rugs (
  [code] VARCHAR (10), 
  [from] INT, 
  [to] INT,
  [color] VARCHAR (10)
);

INSERT INTO rugs VALUES ('RUG001', 0, 1, 'Yellow');
INSERT INTO rugs VALUES ('RUG001', 1, 2, 'Red');
INSERT INTO rugs VALUES ('RUG001', 2, 4, 'Blue');
INSERT INTO rugs VALUES ('RUG001', 3, 5, 'Green');
INSERT INTO rugs VALUES ('RUG002', 0, 1, 'Purple');
INSERT INTO rugs VALUES ('RUG002', 1, 2, 'Orange');

在此示例中，它在对应于地毯 RUG001 的蓝色和绿色的行中重叠。 RUG002 没问题。

如何检查同一张地毯是否有重叠的间隔？

我尝试了什么（但它不起作用）

Select * from RUGS as R1
INNER JOIN RUGS as R2
ON R1.CODE = R2.CODE
WHERE
R1.[FROM] <= R2.[TO] AND R1.[TO] >= R2.[FROM]

Answer 1

对于小型数据集很难确定，但以下内容对您有用吗？使用 Lead/Lag 检查下一个或最后一个范围是否在当前范围内。

with rug as (
select * ,
    Lead([from]) over(partition by code order by [from]) nextfrom, 
    Lag([to]) over(partition by code order by [to]) lastto
from rugs
)
select code, [from], [to], color 
from rug
where nextfrom<[to] or lastto>[from]

Answer 2

这里有两种可能的解决方案。

1. 只是左侧重叠：

SELECT * FROM RUGS R1
INNER JOIN RUGS R2 ON R1.CODE = R2.CODE
WHERE R1.[TO] < R2.[TO] AND R2.[FROM] < R1.[TO] 

--Result
/*
code    from    to  color   code    from    to  color
RUG001  2       4   Blue    RUG001  3       5   Green
*/

1. 所有重叠：

SELECT * FROM RUGS R1
INNER JOIN RUGS R2 ON R1.CODE = R2.CODE
WHERE R1.[FROM] < R2.[FROM] AND R2.[TO] < R1.[TO] 
OR (R2.[FROM] < R1.[FROM] AND  R2.[TO] < R1.[TO] AND R1.[FROM] < R2.[TO])
OR (R1.[FROM] < R2.[FROM] AND  R1.[TO] < R2.[TO] AND R2.[FROM] < R1.[TO])

-- Result
/*
code    from    to  color   code    from    to  color
RUG001  2       4   Blue    RUG001  3       5   Green
RUG001  3       5   Green   RUG001  2       4   Blue
*/