Question

在使用LIKE运算符的可选参数查询中，Escape特殊字符无法正常工作。这是查询的一部分

NAME LIKE  CASE WHEN '%'+@Name+'%' IS NULL THEN NAME ELSE '%'+@Name+'%' END

我以为我可以像

那样

NAME LIKE CASE WHEN '%'+@Name+'%'ESCAPE '\' IS NULL THEN NAME ELSE '%'+@Name+'%' END

但是当我添加转义'\'但它引发了错误。任何帮助??

演示代码：

 set @Name='Restaur\[ant'

      SELECT      [JOB].HOUSE_CODE,  [JOB].JOB_CODE,  [JOB].OPEN_DATE,  [JOB].NAME AS Position,  [JOB].DESCRIPTION,  [RESTAURANT].ZIP_CODE AS ZipCode, 
                           [STATE].STATE_NAME AS State,  [RESTAURANT].CITY_NAME AS City
    FROM          [JOB] INNER JOIN
                           [RESTAURANT] ON  [JOB].HOUSE_CODE =  [RESTAURANT].HOUSE_CODE INNER JOIN
                           [STATE] ON  [RESTAURANT].STATE_CODE =  [STATE].STATE_CODE INNER JOIN
                           [JOB_CODE] ON  [JOB].HOUSE_CODE =  [JOB_CODE].HOUSE_CODE AND  [JOB].JOB_CODE =  [JOB_CODE].JOB_CODE AND 
                           [RESTAURANT].HOUSE_CODE =  [JOB_CODE].HOUSE_CODE
    WHERE     (  [JOB].NAME LIKE  CASE WHEN '%'+@Name+'%' IS NULL THEN  [JOB].NAME ELSE '%'+@Name+'%' END ESCAPE '\' )

Answer 1

将ESCAPE放在CASE语句之外。此外，仅测试@Name为NULL就足够了。

NAME LIKE CASE WHEN @Name IS NULL THEN NAME ELSE '%'+@Name+'%' END ESCAPE `\`

编辑：这里有一些演示代码来说明这项技术。

declare @test table (
    name varchar(100)
)

insert into @test
    (name)
    select 'I am 100% confident this works.' union all
    select 'There can be no doubt.' union all
    select 'I would like to eat in fine restaur[ant some day.'

declare @name varchar(100)

/* Case when @name is NULL */
select name
    from @test
    where name like case when @name is null then name else '%'+@name+'%' end escape '\'

set @name = '100\%'

/* Case when @name has a value with a % */
select name
    from @test
    where name like case when @name is null then name else '%'+@name+'%' end escape '\'

set @name = 'restaur\[ant'

/* Case when @name has a value with a [ */
select name
    from @test
    where name like case when @name is null then name else '%'+@name+'%' end escape '\'

Answer 2

您是否尝试在ESCAPE之前添加空格？

+'%'ESCAPE '\' IS

到此：

+'%' ESCAPE '\' IS

Answer 3

你在找什么？我尝试了你的第一个例子，它表现得像我期望的那样：

CREATE TABLE test2 (
NAME varchar(100)
)

GO

INSERT test2(name) values('Fred')
INSERT test2(name) values('bert')

GO
DECLARE @name VARCHAR(100)
--SET @name='re'
SELECT * FROM test2
WHERE NAME LIKE CASE WHEN '%'+@Name+'%' IS NULL THEN NAME ELSE '%'+@Name+'%' END

如果我为@Name提供一个值，它只返回包含该值的名称，如果我将其保留，则返回所有名称？

Answer 4

你真的想比较'％'+ @ Name +'％ESCAPE'\'为null吗？我想你想稍后放置escape关键字，如下所示：

CASE WHEN '%'+@Name+'%' IS NULL THEN NAME ELSE '%'+@Name+'%' ESCAPE '\' END

Escape无法使用可选参数！

4 个答案: