Question

目前我已经到了

SELECT
    DESCRIPTION,
    LEFT(DESCRIPTION, 
         CASE 
           WHEN CHARINDEX(',', DESCRIPTION) = 0 THEN LEN(DESCRIPTION) 
           ELSE charindex(',', DESCRIPTION) - 1 
         END) AS LEFTDESCRIPTION,
    RIGHT(DESCRIPTION, 
          CASE 
             WHEN CHARINDEX(',',REVERSE(DESCRIPTION)) = 0 THEN '' 
             ELSE charindex(',', DESCRIPTION) - 1 
          END) AS RIGHTDESCRIPTION 
FROM TABLE

但是RIGHT部分似乎不正确，例如：

它得到了一个例子的描述，并且返回“ample，this”而不仅仅是“this”

Answer 1

由于您知道如何获取逗号的内容LEFT，因此可以在REVERSE'd值上使用相同的操作逻辑来获取RIGHT的{{1}}原始字符串，

DECLARE @Var VARCHAR(50) = 'example,this'
SELECT @Var
    , LEFT(@Var, CHARINDEX(',', @Var) - 1)                            -- returns 'example'
    , REVERSE(LEFT(REVERSE(@Var), CHARINDEX(',', REVERSE(@Var)) - 1)) -- returns 'this'
    -- or when using the RIGHT function,
    , RIGHT(@Var, LEN(@Var) - CHARINDEX(',', @Var))                   -- returns 'this'

Per Juan的评论，下面是与上面相同的SELECT（这次选择RIGHT路由而不是REVERSE逻辑），当找不到逗号分隔符时将返回该值，

DECLARE @Var VARCHAR(100) = 'example,this'
SELECT @Var
    , CASE WHEN @Var LIKE '%,%' THEN LEFT(@Var, CHARINDEX(',', @Var) - 1)
           ELSE @Var END
    , CASE WHEN @Var LIKE '%,%' THEN RIGHT(@Var, LEN(@Var) - CHARINDEX(',', @Var))
           ELSE @Var END

Answer 2

我倾向于使用stuff()：

select description,
       left(description, charindex(',', description) - 1)  as leftdescription,
       stuff(description, 1, charindex(',', description), '')  as rightdescription

如果您担心,不在场，请使用case：

select description,
       (case when description like '%,%'
             then left(description, charindex(',', description) - 1)
             else description
        end) as leftdescription,
       (case when description like '%,%'
             then stuff(description, 1, charindex(',', description), '')
        end) as rightdescription

Answer 3

这样做。你非常接近。

SELECT
    DESCRIPTION,
    LEFT(DESCRIPTION, 
         CASE 
           WHEN CHARINDEX(',', DESCRIPTION) = 0 THEN LEN(DESCRIPTION) 
           ELSE charindex(',', DESCRIPTION) - 1 
         END) AS LEFTDESCRIPTION,
    REVERSE(LEFT(Reverse(DESCRIPTION), 
          CASE 
             WHEN CHARINDEX(',',REVERSE(DESCRIPTION)) = 0 THEN '' 
             ELSE charindex(',', REVERSE(DESCRIPTION)) - 1 
          END)) AS RIGHTDESCRIPTION 
FROM TABLE

Answer 4

DECLARE @Var VARCHAR(50) = 'example,this'

SELECT LEFT(@Var, COALESCE(NULLIF(CHARINDEX(',', @Var) - 1, -1), LEN(@Var))) LEFTDESCRIPTION,
       REPLACE(@Var, LEFT(@Var, COALESCE(NULLIF(CHARINDEX(',', @Var), 0), LEN(@Var))), '') RIGHTDESCRIPTION

如何选择'，'左侧的字符，然后选择'，'右侧的字符？

4 个答案: