大尾巴狼

摘要：declare @f1 int, @v1 intset @f1=nullset @v1=nullif @f1=@v1 or (@f1 is null and @v1 is null)print '相同' else print '不同'if @f1<>@v1 or (@f1 is null and @v1 is not null) or (@f1 is not null and @v1 ... 阅读全文