法一: declare @变量 varchar(20) set @变量=isnull(@变量,'') SELECT * FROM mytabl WHERE 字段1 like '%'+@变量+'%' 法二: declare @变量 varchar(20) SELECT * FROM mytabl WHERE (@变量 is null or 字段1 like '%'+@变量+'%')
declare @变量 varchar(10) SELECT * FROM mytabl WHERE @变量 is null or 字段1 like '%'+@变量+'%'
SELECT * FROM mytabl WHERE (@变量 is null or @变量 ="" or 字段1=@变量)
declare @变量 varchar(20)
set @变量=isnull(@变量,'')
SELECT * FROM mytabl WHERE 字段1 like '%'+@变量+'%'
法二:
declare @变量 varchar(20)
SELECT * FROM mytabl WHERE (@变量 is null or 字段1 like '%'+@变量+'%')
declare @变量 varchar(10)
SELECT * FROM mytabl WHERE @变量 is null or 字段1 like '%'+@变量+'%'
SELECT * FROM mytabl WHERE (@变量 is null or @变量 ="" or 字段1=@变量)