Question

为什么这项工作：

SELECT * FROM Companies  WHERE CompanyCode LIKE '%' AND BusinessUnitShortName LIKE 'CO%'

虽然意味着这不起作用：

DECLARE @WHERECondition NVARCHAR(200) = ''
SET @WHERECondition = '''%'' AND BusinessUnitShortName LIKE ''CO%'''

SELECT * FROM Companies WHERE CompanyCode LIKE  @WHERECondition
SELECT  @WHERECondition

Answer 1

要完成这项工作，您需要使用动态sql，如

DECLARE @WHERECondition NVARCHAR(200) = ''
SET @WHERECondition = '''%'' AND BusinessUnitShortName LIKE ''CO%'''
declare @sql nvarchar(Max)

Set @sql='SELECT * FROM Companies WHERE CompanyCode LIKE'+@WHERECondition

exec sp_executesql @sql

如果您没有使用动态sql，那么您需要提供列名，因为SQL解析器将在解析查询时查找列，如果找不到则会导致错误。

Answer 2

您需要使用动态SQL来实现您想要的效果。您当前的方法会被评估为：

SELECT * 
FROM Companies 
WHERE CompanyCode LIKE '''%'' AND BusinessUnitShortName LIKE ''CO%'''

你真正想要的更像是这样：

DECLARE @sql NVARCHAR(MAX) = ''
DECLARE @WHERECondition =  '''%'' AND BusinessUnitShortName LIKE ''CO%'''

SET @sql = 'SELECT * FROM Companies WHERE CompanyCode LIKE ' + @WHERECondition
EXEC(@sql);

将评估：

SELECT * FROM Companies WHERE CompanyCode LIKE '%' AND BusinessUnitShortName LIKE 'CO%'

比变量中的Like语句更多

2 个答案: