我是SQL Server和Stack Overflow的新手,请原谅我的错误。
在一列中按字母顺序排序一个值是否可能?这是我的表格:
NAME
......
XZYVW
EBACD
我的结果应该像下面这样。
NAME
......
VWXYZ
ABCDE
有什么办法可以得到这个?
我是SQL Server和Stack Overflow的新手,请原谅我的错误。
在一列中按字母顺序排序一个值是否可能?这是我的表格:
NAME
......
XZYVW
EBACD
NAME
......
VWXYZ
ABCDE
即使有一些优化的可能性。这里有两个函数使用冒泡排序来排序字符。
CREATE FUNCTION udf_SortString
(
@string VARCHAR(1000)
)
RETURNS VARCHAR(1000)
AS
BEGIN
DECLARE @len TINYINT
DECLARE @i TINYINT
DECLARE @currentchar CHAR(1)
DECLARE @swapped BIT
DECLARE @begin BIT
DECLARE @nextchar CHAR(1)
SET @begin = 1
SET @len = LEN(@string)
SET @i = 1
WHILE @begin = 1 OR @swapped = 1
BEGIN
SET @swapped = 0
SET @i = 1
SET @begin = 0
WHILE @i <= @len
BEGIN
SET @currentchar = SUBSTRING(@string, @i, 1)
SET @nextchar = SUBSTRING(@string, @i + 1, 1)
IF @currentchar > @nextchar AND (@nextchar > '')
BEGIN
SET @string = dbo.udf_swap(@string, @i, @i + 1)
SET @swapped = 1
END
SET @i = @i + 1
END
END
RETURN(@string)
END
功能 2:
CREATE FUNCTION dbo.udf_Swap
(
@fullstring VARCHAR(1000),
@charlocation1 TINYINT,
@charlocation2 TINYINT
)
RETURNS VARCHAR(1000)
AS
BEGIN
DECLARE @returnval varchar(1000)
DECLARE @begin VARCHAR(1000), @middle VARCHAR(1000), @end VARCHAR(1000)
DECLARE @firstchar CHAR(1), @secondchar CHAR(1), @len INT
SET @fullstring = LTRIM(RTRIM(@fullstring))
SET @len = LEN(@fullstring)
IF @charlocation1 > @len OR @charlocation2 > @len
SET @returnval = @fullstring
ELSE
BEGIN
SET @firstchar = SUBSTRING(@fullstring, @charlocation1, 1)
SET @secondchar = SUBSTRING(@fullstring, @charlocation2, 1)
SET @begin = LEFT(@fullstring, (@charlocation1-1))
SET @middle = SUBSTRING(@fullstring, @charlocation1+1, (@charlocation2-@charlocation1)-1)
SET @end = SUBSTRING(@fullstring, @charlocation2+1, @len)
SET @returnval = @begin + @secondchar + @middle + @firstchar + @end
END
RETURN(@returnval)
END
结果:
select dbo.udf_SortString('zxcvbfgrtyuijklm')
--Returns bcfgijklmrtuvxyz
这将按字母顺序排序,而不使用函数。在@Shnugo的评论后进行了优化重写。
DECLARE @t table(col varchar(4000))
INSERT @t values('kdjfh'),('zug')
SELECT
Col,
(
SELECT
chr
FROM
(SELECT TOP(LEN(Col))
SUBSTRING(Col,ROW_NUMBER() OVER(ORDER BY 1/0),1)
FROM sys.messages) A(Chr)
ORDER by chr
FOR XML PATH(''), type).value('.', 'varchar(max)'
) SortedCol
FROM
@t
结果:
col SortedCol
kdjfh dfhjk
zug guz
CREATE FUNCTION dbo.Alphaorder (@str VARCHAR(50))
returns VARCHAR(50)
BEGIN
DECLARE @len INT,
@cnt INT =1,
@str1 VARCHAR(50)='',
@output VARCHAR(50)=''
SELECT @len = Len(@str)
WHILE @cnt <= @len
BEGIN
SELECT @str1 += Substring(@str, @cnt, 1) + ','
SET @cnt+=1
END
SELECT @str1 = LEFT(@str1, Len(@str1) - 1)
SELECT @output += Sp_data
FROM (SELECT Split.a.value('.', 'VARCHAR(100)') Sp_data
FROM (SELECT Cast ('<M>' + Replace(@str1, ',', '</M><M>') + '</M>' AS XML) AS Data) AS A
CROSS APPLY Data.nodes ('/M') AS Split(a)) A
ORDER BY Sp_data
RETURN @output
END
结果:
SELECT dbo.Alphaorder ('XZYVW') --VWXYZ
不是mssql,但在Presto中我找到了这种方法。也许有人可以转换它,或者找到更好的方法来将字符串拆分为数组,排序并重新连接:
SELECT ARRAY_JOIN(ARRAY_SORT(REGEXP_EXTRACT_ALL('aaffed', '.')), '') --> 'aadeff'
WHILE
循环,标量函数...)。t-clausen.dk的答案更好,但在执行时会使用太多行。你可能想要在这里阅读一下... - Shnugo