方法1：

当出版社筛选条件为null，该如何写SQL呢？

1 DECLARE @publishers VARCHAR(50);

2 SELECT * FROM dbo.Book WHERE Publishers=ISNULL(@publishers,Publishers)

方法2：

declare @cinv varchar(50)

select * from inventory where 1=1 and (cInvName=@cinv or @cinv is null)

方法3：

DECLARE @name VARCHAR(100),@page INT =1SET @name='张三'

DECLARE @sql VARCHAR(1000)

SET @sql='select * from myTable where 1=1'IF @name IS NOT NULL SET @sql=@sql+' and name='''+@name+''''--字符型注意引号个数IF @page IS NOT NULL SET @sql=@sql+' and page='+LTRIM(@page)--int类型注意转换为字符型--PRINT @sql EXEC(@sql)