删除 SQL Server 2008 R2 中测试的最后三个字符

Question

我正在尝试删除邮政编码的最后三个字符，但问题是邮政编码可能是 eneter 字段类型 varchar(max) 不知道我怎么不能删除最后一个字符在文本值中。

目前，当我尝试运行代码时，出现以下错误

Invalid length parameter passed to the LEFT or SUBSTRING function

代码：

SELECT
      c.[postcode],
      left ( ltrim(rTrim(c.[postcode])) ,len(ltrim(rTrim(c.[postcode])))-4) as ode
FROM [testing].[dbo].[canidateinfo] as c

Answer 1

这样的事情会成功吗：

SELECT  LEFT(PostCode, CHARINDEX(' ', Postcode)+1) PostCodeSector
FROM testing.dbo.canidateinfo

** 更新 **

CREATE TABLE #postcodeTest (postcode varchar(max))
insert into #postcodeTest
Values
('AB3 4FY'),
('AB34FY'),
('M504FY'),
('M50 4FY')

SELECT  DISTINCT
        CASE (isnumeric(SUBSTRING([Postcode] , 2 , 1))) 
            WHEN 1 THEN LEFT ([Postcode] , 2) 
            ELSE LEFT ([Postcode] , 3) 
        END PcodeArea
FROM    #postcodeTest

Answer 2

这将排除最后 3 个字符：

SELECT
      c.[postcode],
      ltrim(substring( c.postcode , -2, len(c.postcode))) code
FROM [testing].[dbo].[canidateinfo] as c

示例：

DECLARE @t table(postcode varchar(20))
INSERT @t values('1234567'),('32'),('abcde'),(' aa123'),('  aa  ')

SELECT 
  postcode, 
  ltrim(substring( postcode , -2, len(postcode))) as code
FROM @t

结果：

postcode  code
1234567   1234
32        <blank>
abcde     ab
 aa123    aa
  aa      <blank>

Answer 3

如果您传递的变量为 null 或小于 3（因为您在查询中指定了 -3），那么它会在您得到时抛出错误

select a.[postcode],
      iif(len(a.[postcode])<3,a.[postcode],left(a.[postcode],len(lTrim(a.[postcode]))-3) as trimmed
FROM [testing].[dbo].[canidateinfo] as a

我使用了 iif(exp,true,false) 函数，它会检查长度并根据它工作...

删除 SQL Server 2008 R2 中测试的最后三个字符

Delete last three characters of test in SQL Server 2008 R2

sql

sql-server

sql-server-2008-r2