我有以下查询：
SELECT
series, scott
FROM
stampitemdetails
WHERE
scott REGEXP '^C[0-9]'
ORDER BY SUBSTR(scott, 1, 1) , CAST(SUBSTR(scott, 2, 100) AS UNSIGNED)
它几乎以正确的顺序返回我的行，但是当数字后面有字母时，它们有时会不按顺序。其他似乎正确排序。返回的内容如下：
series scott
Airmail Stamps C1
Airmail Stamps C2
Airmail Stamps C3
Airmail Stamps C3a
Airmail Stamps C4
Airmail Stamps C5
Airmail Stamps C6
Airmail Stamps C7
Airmail Stamps C8
Airmail Stamps C9
Airmail Stamps C10b
Airmail Stamps C10a
Airmail Stamps C10
Airmail Stamps C11
Airmail Stamps C11a
Airmail Stamps C12
Airmail Stamps C12a
Airmail Stamps C13
Airmail Stamps C14
Airmail Stamps C15
Airmail Stamps C16
Airmail Stamps C17
Airmail Stamps C18
Airmail Stamps C19
Airmail Stamps C20
Airmail Stamps C21
Airmail Stamps C22
Airmail Stamps C23
Airmail Stamps C23a
Airmail Stamps C23b
Airmail Stamps C23c
Airmail Stamps C24
Airmail Stamps C25
Airmail Stamps C25a
Airmail Stamps C25b
Airmail Stamps C26a
Airmail Stamps C26
Airmail Stamps C27
Airmail Stamps C28
Airmail Stamps C29
Airmail Stamps C30
Airmail Stamps C31
Airmail Stamps C32
Airmail Stamps C33
Airmail Stamps C34
Airmail Stamps C34a
Airmail Stamps C35
Airmail Stamps C35a
Airmail Stamps C35b
Airmail Stamps C36
Airmail Stamps C36a
Airmail Stamps C37
Airmail Stamps C38
Airmail Stamps C39
Airmail Stamps C39a
Airmail Stamps C39b
Airmail Stamps C39c
Airmail Stamps C40
Airmail Stamps C41
Airmail Stamps C42
Airmail Stamps C43
Airmail Stamps C44
Airmail Stamps C45
Airmail Stamps C46
Airmail Stamps C47
Airmail Stamps C48
Airmail Stamps C49
Airmail Stamps C50
Airmail Stamps C51b
Airmail Stamps C51
Airmail Stamps C51a
如果您查看C10，则应按照以下顺序进行操作：
C10
C10a
C10b
C51应该是：
C51
C51a
C51b
有人可以解释出什么问题以及如何解决此查询吗？谢谢！
答案 0 :(得分：3)
我认为，您遇到的问题是要进行无符号签名的CAST忽略了您的a和b，因此scott列的该部分以随机顺序出现。我倾向于尝试
SELECT
series, scott
FROM
stampitemdetails
WHERE
scott REGEXP '^C[0-9]'
ORDER BY SUBSTR(scott, 1, 1) , CAST(SUBSTR(scott, 2, 100) AS UNSIGNED), scott
即将整列添加到ORDER BY序列的末尾，作为平局。