我想在下表中找到空白:
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 );
Expeced结果类似于:
10 | 2-3
11 | 3-4
11 | 6
或
10 | 2
10 | 3
11 | 3
11 | 4
11 | 6
我知道,colum'Value'的值在0到7之间。
是否可以使用MySQL进行此操作?
编辑1
根据答案,我来了:
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
但现在我只是
10 | 2 | 3
拜托,有人知道,如何解决?
答案 0 :(得分:1)
您可以使用not exists
:
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
条款非常重要,因此您不会报告每个id
的最终值。
编辑:
这是一种更好的方法:
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);