在 T-SQL 中删除字符串中的最后一个字符？

Question

How do I remove the last character in a string in T-SQL ?

For example:

'TEST STRING'

to return:

'TEST STRIN'

Answer 1

eg

DECLARE @String VARCHAR(100)
SET @String = 'TEST STRING'

-- Chop off the end character
SET @String = 
     CASE @String WHEN null THEN null 
     ELSE (
         CASE LEN(@String) WHEN 0 THEN @String 
            ELSE LEFT(@String, LEN(@String) - 1) 
         END 
     ) END


SELECT @String

Answer 2

If for some reason your column logic is complex (case when ... then ... else ... end), then the above solutions causes you to have to repeat the same logic in the len() function. Duplicating the same logic becomes a mess. If this is the case then this is a solution worth noting. This example gets rid of the last unwanted comma. I finally found a use for the REVERSE function.

select reverse(stuff(reverse('a,b,c,d,'), 1, 1, ''))

Answer 3

试试这个：

select substring('test string', 1, (len('test string') - 1))

Answer 4

If your string is empty,

DECLARE @String VARCHAR(100)
SET @String = ''
SELECT LEFT(@String, LEN(@String) - 1)

then this code will cause error message 'Invalid length parameter passed to the substring function.'

You can handle it this way:

SELECT LEFT(@String, NULLIF(LEN(@String)-1,-1))

It will always return result, and NULL in case of empty string.

Answer 5

即使源文本/var 为 null 或空，这也能工作：

SELECT REVERSE(SUBSTRING(REVERSE(@a), 2, 9999))

Answer 6

select left('TEST STRING', len('TEST STRING')-1)

Answer 7

@result = substring(@result, 1, (LEN(@result)-1))

Answer 8

如果您的 coloumn 是text而不是varchar ，那么您可以使用：

SELECT SUBSTRING(@String, 1, NULLIF(DATALENGTH(@String)-1,-1))

Answer 9

If you want to do this in two steps, rather than the three of REVERSE-STUFF-REVERSE, you can have your list separator be one or two spaces. Then use RTRIM to trim the trailing spaces, and REPLACE to replace the double spaces with ','

select REPLACE(RTRIM('a  b  c  d  '),'  ', ', ')

However, this is not a good idea if your original string can contain internal spaces.

Not sure about performance. Each REVERSE creates a new copy of the string, but STUFF is a third faster than REPLACE.

also see this

Answer 10

I can suggest this -hack- ;).

select 
    left(txt, abs(len(txt + ',') - 2))
from 
    t;

SQL Server Fiddle Demo

Answer 11

This is quite late, but interestingly never mentioned yet.

select stuff(x,len(x),1,'')

ie:

take a string x
go to its last character
remove one character
add nothing

Answer 12

you can create function

CREATE FUNCTION [dbo].[TRUNCRIGHT] (@string NVARCHAR(max), @len int = 1)
RETURNS NVARCHAR(max)
AS
BEGIN
    IF LEN(@string)<@len
        RETURN ''
    RETURN LEFT(@string, LEN(@string) - @len)
END

Answer 13

获取最后一个字符

Right(@string, len(@String) - (len(@String) - 1))

Answer 14

Try this

DECLARE @String VARCHAR(100)
SET @String = 'TEST STRING'
SELECT LEFT(@String, LEN(@String) - 1) AS MyTrimmedColumn

Answer 15

I encountered this problem and this way my problem was solved:

 Declare @name as varchar(30)='TEST STRING' Select left(@name, len(@name)-1) as AfterRemoveLastCharacter

Answer 16

My answer is similar to the accepted answer, but it also check for Null and Empty String.

DECLARE @String VARCHAR(100)

SET @String = 'asdfsdf1'

-- If string is null return null, else if string is empty return as it is, else chop off the end character
SET @String = Case @String when null then null else (case LEN(@String) when 0 then @String else LEFT(@String, LEN(@String) - 1) end ) end

SELECT @String

Answer 17

I love @bill-hoenig 's answer; however, I was using a subquery and I got caught up because the REVERSE function needed two sets of parentheses. Took me a while to figure that one out!

SELECT
   -- Return comma delimited list of all payment reasons for this Visit
   REVERSE(STUFF(REVERSE((
        SELECT DISTINCT
               CAST(CONVERT(varchar, r1.CodeID) + ' - ' + c.Name + ', ' AS VARCHAR(MAX))
          FROM VisitReason r1
          LEFT JOIN ReasonCode c        ON c.ID = r1.ReasonCodeID
         WHERE p.ID = r1.PaymentID
         FOR XML PATH('')
              )), 1, 2, ''))                        ReasonCode
  FROM Payments p

Answer 18

要通过修剪特定列的最后 N 个字符来更新记录：

UPDATE tablename SET columnName = LEFT(columnName , LEN(columnName )-N) where clause

Answer 19

Try It :

  DECLARE @String NVARCHAR(100)
    SET @String = '12354851'
    SELECT LEFT(@String, NULLIF(LEN(@String)-1,-1))

Answer 20

declare @string varchar(20)= 'TEST STRING'
Select left(@string, len(@string)-1) as Tada

output:

Tada
--------------------
TEST STRIN

Answer 21

Try this,

DECLARE @name NVARCHAR(MAX) SET @name='xxxxTHAMIZHMANI****'SELECT Substring(@name, 5, (len(@name)-8)) as UserNames

And the output will be like, THAMIZHMANI

Answer 22

declare @x varchar(20),@y varchar(20)
select @x='sam'
select 
case when @x is null then @y
      when @y is null then @x
      else @x+','+@y
end


go

declare @x varchar(20),@y varchar(20)
select @x='sam'
--,@y='john'
DECLARE @listStr VARCHAR(MAX)   

SELECT @listStr = COALESCE(@x + ', ' ,'') +coalesce(@y+',','')
SELECT left(@listStr,len(@listStr)-1)