如何检查一个值是否为 NULL [或者] = @param
(其中@param为null)
示例:
Select column1 from Table1
where column2 IS NULL => works fine
如果我想用@param替换比较值(IS NULL),应该怎么做?
Select column1 from Table1
where column2 = @param => this works fine until @param got some value in it and if is null never finds a record.
这个怎么实现?