我分享一个解决方案，在我看来，它非常快，但安装起来有点繁琐。它在Microsoft SQL Server 2008 R2 (SP3)上工作得很好:

在数据库所在的服务器上安装Sql Regex程序集。安装步骤如下: https://github.com/DevNambi/sql-server-regex#installation 在数据库中创建函数dbo。TRIM，它基于RegexReplace()标量函数(https://github.com/DevNambi/sql-server-regex#replace):

CREATE FUNCTION [dbo].[TRIM](@text NVARCHAR(MAX))
  RETURNS NVARCHAR(MAX) --WITH SCHEMABINDING 
BEGIN

-- This function removes:
-- 1. invisible characters,
-- 2. repeated blank spaces and
-- 3. the spaces at the beginning and at the end of the text.

    RETURN (CASE
        WHEN @text is NULL 
            THEN NULL
        ELSE

            dbo.RegexReplace((dbo.RegexReplace(dbo.RegexReplace(@text, N'['+Nchar(0)+N'-'+Nchar(32)+Nchar(8192)+N'-'+Nchar(8202)+Nchar(160)+Nchar(5760)+Nchar(6158)+Nchar(8232)+Nchar(8233)+Nchar(8239)+Nchar(8287)+Nchar(65440)+Nchar(12288) +N']+', N'[}'), N'[\[\}]+', ' ')), N'^\s+|\s+$','')  

    END);
END
GO

....................

使用方法:

declare @txt NVARCHAR(MAX) = N' Hello,'+Nchar(12288)+N'          my      '+NCHAR(160)+N'name'+Nchar(0)+N'     is John'+NCHAR(11)+N'            Doe';

select dbo.TRIM(@txt) as Result -- Result: "Hello, my name is John Doe"

....................

更新:

要完全删除所有空格，您可以创建以下函数:

CREATE FUNCTION [dbo].[TRIM_SPACES](@text NVARCHAR(MAX))
  RETURNS NVARCHAR(MAX) --WITH SCHEMABINDING 
BEGIN
    RETURN (CASE WHEN @text is NULL THEN NULL ELSE
            dbo.RegexReplace(@text, N'['+Nchar(0)+N'-'+Nchar(32)+Nchar(8192)+N'-'+Nchar(8202)+Nchar(160)+Nchar(5760)+Nchar(6158)+Nchar(8232)+Nchar(8233)+Nchar(8239)+Nchar(8287)+Nchar(65440)+Nchar(12288) +N']+', N'')
    END)
END
GO

....................

使用方法:

declare @txt NVARCHAR(MAX) = N' Hello,'+Nchar(12288)+N'          my      '+NCHAR(160)+N'name'+Nchar(0)+N'     is John'+NCHAR(11)+N'            Doe';

select dbo.TRIM_SPACES(@txt) as Result -- Result: "Hello,mynameisJohnDoe"

参考本博客:

首先，创建示例表和数据:

CREATE TABLE tbl_RemoveExtraSpaces
(
     Rno INT
     ,Name VARCHAR(100)
)
GO

INSERT INTO tbl_RemoveExtraSpaces VALUES (1,'I    am     Anvesh   Patel')
INSERT INTO tbl_RemoveExtraSpaces VALUES (2,'Database   Research and     Development  ')
INSERT INTO tbl_RemoveExtraSpaces VALUES (3,'Database    Administrator     ')
INSERT INTO tbl_RemoveExtraSpaces VALUES (4,'Learning    BIGDATA    and       NOSQL ')
GO

脚本选择字符串没有额外的空格:

SELECT
     [Rno]
    ,[Name] AS StringWithSpace
    ,LTRIM(RTRIM(REPLACE(REPLACE(REPLACE([Name],CHAR(32),'()'),')(',''),'()',CHAR(32)))) AS StringWithoutSpace
FROM tbl_RemoveExtraSpaces

结果:

Rno         StringWithSpace                                 StringWithoutSpace
----------- -----------------------------------------  ---------------------------------------------
1           I    am     Anvesh   Patel                      I am Anvesh Patel
2           Database   Research and     Development         Database Research and Development
3           Database    Administrator                       Database Administrator
4           Learning    BIGDATA    and       NOSQL          Learning BIGDATA and NOSQL

这对我来说很有用:

CREATE FUNCTION dbo.TRIM(@String VARCHAR(MAX))
RETURNS VARCHAR(MAX)
BEGIN
    RETURN LTRIM(RTRIM(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(@String,CHAR(10),'[]'),CHAR(13),'[]'),char(9),'[]'),CHAR(32),'[]'),'][',''),'[]',CHAR(32))));
END
GO

.

一个功能版本(udf)，删除空格，cr, lf，制表符或可配置。

select Common.ufn_RemoveWhitespace(' 234   asdf   wefwef 3  x   ', default) as S

结果:234 asdfwefwef3x

alter function Common.RemoveWhitespace
(
    @pString nvarchar(max),
    @pWhitespaceCharsOpt nvarchar(max) = null -- default: tab, lf, cr, space 
)  
returns nvarchar(max) as
/*--------------------------------------------------------------------------------------------------
    Purpose:   Compress whitespace

    Example:  select Common.ufn_RemoveWhitespace(' 234   asdf   wefwef 3  x   ', default) as s 
              -- Result: 234asdfwefwef3x

    Modified    By          Description
    ----------  ----------- --------------------------------------------------------------------
    2018.07.24  crokusek    Initial Version 
  --------------------------------------------------------------------------------------------------*/ 
begin    
    declare 
        @maxLen bigint = 1073741823, -- (2^31 - 1) / 2 (https://stackoverflow.com/a/4270085/538763)
        @whitespaceChars nvarchar(30) = coalesce(
            @pWhitespaceCharsOpt, 
            char(9) + char(10) + char(13) + char(32));  -- tab, lf, cr, space

    declare
        @whitespacePattern nvarchar(30) = '%[' + @whitespaceChars + ']%',
        @nonWhitespacePattern nvarchar(30) = '%[^' + @whitespaceChars + ']%',
        @previousString nvarchar(max) = '';

    while (@pString != @previousString)
    begin
        set @previousString = @pString;

        declare
            @whiteIndex int = patindex(@whitespacePattern, @pString);

        if (@whiteIndex > 0)
        begin                   
            declare 
                @whitespaceLength int = nullif(patindex(@nonWhitespacePattern, substring(@pString, @whiteIndex, @maxLen)), 0) - 1;                

            set @pString = 
                substring(@pString, 1, @whiteIndex - 1) + 
                iif(@whiteSpaceLength > 0, substring(@pString, @whiteIndex + @whiteSpaceLength, @maxLen), '');
        end        
    end        
    return @pString;
end
go

取代()函数:

REPLACE(field, ' ', '')

我今天遇到了这个问题，替换/修剪成功了，见下文。

update table_foo 
set column_bar  = REPLACE(LTRIM(RTRIM(column_bar)), '  ', '')

前后:

old-bad:  column_bar    |   New-fixed:   column_bar
       '  xyz  '        |                'xyz'   
       '  xyz  '        |                'xyz' 
       '  xyz  '        |                'xyz' 
       '  xyz  '        |                'xyz' 
       '  xyz  '        |                'xyz' 
       '  xyz  '        |                'xyz'