Question

select max(some_column1), some_column2 from(
    select distinct some_column1, some_column2 from table1 where some_column1 = (select max(some_column1) from table1)
    union all
    select distinct some_column1, some_column2 from table2 where some_column1 = (select max(some_column1) from table2) 
    union all
    select distinct some_column1, some_column2 from table3 where some_column1 = (select max(some_column1) from table3)
) as max_result

此查询完全符合我的要求。唯一的问题是，当我从some_column1获得最大结果时，我还想获得与max（some_column1）相对应的some_column2。相反，我得到了3个结果。我需要将其限制为一个结果。 some_column2必须与max（some_column1）在同一个表中。除了将结果存储到临时表中之外，还有这样做吗？所有帮助表示赞赏。提前谢谢！

Answer 1

给它一个镜头..它有点复杂......但应该工作..如果最大值有一个平局，并且你想要所有的那么，那么只需替换=检查where子句与IN

select max_result.some_column1,max_result.some_column2 from (
    select distinct some_column1, some_column2 from table1 where some_column1 = (select max(some_column1) from table1)
    union all
    select distinct some_column1, some_column2 from table2 where some_column1 = (select max(some_column1) from table2) 
    union all
    select distinct some_column1, some_column2 from table3 where some_column1 = (select max(some_column1) from table3)
) max_result
where max_result.some_column1 =
(select max(some_column1) from
(
    select distinct some_column1, some_column2 from table1 where some_column1 = (select max(some_column1) from table1)
    union all
    select distinct some_column1, some_column2 from table2 where some_column1 = (select max(some_column1) from table2) 
    union all
    select distinct some_column1, some_column2 from table3 where some_column1 = (select max(some_column1) from table3)
))

Answer 2

我认为最简单的方法是按some_column1排序并取第一行。这将获得some_column1具有更大值的行，并且仍然可以访问some_column2。

尝试：

select top 1 some_column1, some_column2 from(
    select distinct some_column1, some_column2 from @table1 where some_column1 = (select max(some_column1) from @table1)
    union all
    select distinct some_column1, some_column2 from @table2 where some_column1 = (select max(some_column1) from @table2) 
    union all
    select distinct some_column1, some_column2 from @table3 where some_column1 = (select max(some_column1) from @table3)
) as max_result
order by some_column1 desc

如何从多个表中选择一列为max（）的多列

2 个答案: