我想在下表中找出差距:
create table sequence
(
`Id` int,
`Value` int not null,
PRIMARY KEY (`Id`,`Value`)
);
insert into sequence
( `Id`, `Value` )
values
(10, 0 ),
(10, 1 ),
(10, 4 ),
(10, 5 ),
(10, 6 ),
(10, 7 ),
(11, 0 ),
(11, 1 ),
(11, 2 ),
(11, 5 ),
(11, 7 );
实验结果如下:
10 | 2-3
11 | 3-4
11 | 6
或
10 | 2
10 | 3
11 | 3
11 | 4
11 | 6
我知道,column'value'的值在0到7之间。
可以用mysql来实现吗?
编辑1
根据我的回答:
SELECT Tbl1.Id,
startseqno,
Min(B.Value) - 1 AS END
FROM (SELECT Id,
Value + 1 AS StartSeqNo
FROM SEQUENCE AS A
WHERE NOT EXISTS (SELECT *
FROM SEQUENCE AS B
WHERE B.Id = A.id
AND B.Value = A.Value + 1)
AND Value < (SELECT Max(Value)
FROM SEQUENCE B
WHERE B.Id = A.Id)) AS Tbl1,
SEQUENCE AS B
WHERE B.Id = Tbl1.Id
AND B.Value > Tbl1.startseqno
但现在我变得
10 | 2 | 3
拜托,有人知道怎么修吗?
sqlfiddle
最佳答案
您可以使用not exists
来完成此操作:
select s.*
from sequence s
where not exists (select 1 from sequence s2 where s2.id = s.id and s2.value = s.value + 1) and
exists (select 1 from sequence s2 where s2.id = s.id and s2.value > s.value);
exists
子句很重要,因此您不必为每个id
报告最终值。编辑:
下面是一个更好的方法:
select s.value + 1 as startgap,
(select min(s2.value) - 1 from sequence s2 where s2.id = s.id and s2.value > s.value) as endgap
from sequence s
where not exists (select 1 from sequence s2 where s2.id = s.id and s2.value = s.value + 1) and
exists (select 1 from sequence s2 where s2.id = s.id and s2.value > s.value);