sql - 如何对版本号进行排序，例如 ‘A’ 、 ‘B’ 、 ‘AA’ 、 ‘AB’ 和 ‘AAA’ ？

Question

引用这个问题:How do I grab only the latest Invoice Number

我接受了使用 MAX 函数的答案，但 Robert McKee 指出这将导致排序值，例如:

‘A’
‘AA’
‘AAA’
‘AB’
‘B’

When what I need is:

‘A’
‘B’
‘AA’
‘AB’
‘AAA’

I am trying to find a way to find the latest Version of an Invoice. The accepted answer from the referenced question will work up to a point. And it did satisfy my question... But now a new problem deserves its own question and not for me to go back and modify my original question. So…

The only thing I have to work with is the Invoice Number itself. The Invoice number has a format of #####XXX, where ##### is the actual Invoice Number and the XXX is the version number. XXX can be anywhere from ‘A’ to ‘ZZZ’.

Here is my attempt to find a plausible work around (a sql test case):

DECLARE @TempTable TABLE (MyNumber int, MyString varchar(15));

INSERT @TempTable
VALUES (100, 'A'), (100, 'AAZ'), (100, 'B'), (100, 'AZ'), (100, 'C'), (100, 'Z'), (100, 'AA'), (100, 'AB');

SELECT TOP 1
RTRIM(CAST(MyNumber AS NVARCHAR(15)) + MyString) AS InvoiceNumber
FROM @TempTable
ORDER BY RIGHT(LEFT(MyString + SPACE(2), 3), 1) DESC, RIGHT(LEFT(MyString + SPACE(2), 2), 1) DESC, LEFT(MyString, 1) DESC;

有人愿意提供更好的答案或为我指出正确的方向来清理我的吗？

提前致谢，

Answer 1

尝试这样的事情:

ORDER BY LEN(myValue),myValue

这将排序 1 个字符，然后是 2 个字符，依此类推...