Question

表A有一个列X，它是由表B中Y和Z列（它们都是浮点数）的串联组成的int。我想以类似于这样的方式连接表A和B：

select *
from tableA a inner join tableB b
on a.X = b.cast(concat(cast(b.Y as varchar), cast(b.Z as varchar)) as integer

除此之外，显然，我的例子没有正确完成。

Answer 1

你可以这样做：

select * 
from tableA a 
inner join tableB b 
on a.X = cast(cast(b.Y as varchar) + cast(b.Z as varchar) as int)

如果你的任何浮点数都有小数点，转换为int将会失败。

，例如，这有效：

declare @f1 as float
declare @f2 as float
set @f1 = 1
set @f2 = 7
select cast(cast(@f1 as varchar) + cast(@f2 as varchar) as int)

输出： 17

但这不是：

declare @f1 as float
declare @f2 as float
set @f1 = 1.3
set @f2 = 7
select cast(cast(@f1 as varchar) + cast(@f2 as varchar) as int)

输出： Conversion failed when converting the varchar value '1.37' to data type int.

Answer 2

听起来像计算列的作业，然后它可以索引。

Answer 3

你能在名为x的b中创建另一列，其中包含你想要的值吗？然后加入A很容易。