sql-server - SQL Server Ltrim 或子字符串仅获取电子邮件地址

Question

我有这种情况：

John Doe johndoe@email.com
John johndoe@email.com

我想要的只是解析如下：

John Doe
John

换句话说，仅删除电子邮件地址。

我试过这个：

SELECT
                (CASE WHEN CHARINDEX(‘ ‘, REVERSE(column1)) > 0 THEN Left(column1, CHARINDEX(‘ ‘, REVERSE(column1)) – 1)
                ELSE column1
                END) AS column1
FROM Book1

Answer 1

你在正确的轨道上......只需添加 len 函数并删除“负 1”

SELECT  (CASE WHEN CHARINDEX(' ', REVERSE(column1)) > 0 THEN Left(column1, len (column1) - CHARINDEX(' ', REVERSE(column1)))
                ELSE column1
                END) AS column1
FROM Book1

Answer 2

DECLARE @Str VARCHAR(MAX) = 'John Doe johndoe@email.com'


 SELECT LEFT(@Str, LEN(@Str) - LEN(REVERSE(SUBSTRING(REVERSE(@Str), 1, CHARINDEX(' ', REVERSE(@Str)) - 1))))