Sql Query结果问题

Question

我正在尝试检索此列值的第二个单词，但它显示为空白
我的疑问是：

select ltrim(
  substring(companyname,
  charindex(' ',companyname),
  CHARINDEX(
    ' ',
    ltrim(
      SUBSTRING(
        companyname,
        charindex(' ',companyname),
        LEN(companyname) - charindex(' ',companyname))
      )
    )
  )
)
from pmweb_companies
where companyname = '7x24 Exchange'

结果应该返回：Exchange 但它显示空白。

Answer 1

这是因为该查询要求总单词数超过两个，这意味着您要解析的字符串中至少需要两个空格。

如果你想要排除第一个单词并从第二个单词中获取任何内容，你可以使用类似的东西

select ltrim(
         substring(
           companyname,
           charindex(' ', companyname),
           len(companyname) - charindex(' ', companyname) + 1
         )
       );

如果您想完全改为第二个单词，可以将查询破解为

select ltrim(
  substring(companyname,
  charindex(' ', companyname),
  CHARINDEX(
    ' ',
    ltrim(
      SUBSTRING(
        companyname + ' fake',
        charindex(' ', companyname),
        LEN(companyname + ' fake') - charindex(' ', companyname))
      )
    )
  )
)
from pmweb_companies
where companyname = '7x24 Exchange'

修改

如果我正确理解您的评论，如果字符串只有一个单词，则查询应返回空白。如果是这种情况，您可以在case

中使用select声明

select  case
          when charindex(
                 ' ',
                 substring(
                   companyname,
                   charindex(' ', companyname),
                   LEN(companyname) - charindex(' ', companyname) + 1
                 )
               ) = 0 /* this means there's less than two words */
          then '' /* you can place something else here, as you prefer */
          else
            ltrim(
              substring(companyname,
              charindex(' ', companyname),
              CHARINDEX(
                ' ',
                ltrim(
                  SUBSTRING(
                    companyname + ' fake',
                    charindex(' ', companyname),
                    LEN(companyname + ' fake') - charindex(' ', companyname))
                  )
                )
              )
            )
          end
from pmweb_companies
where companyname = '7x24 Exchange'