sql - 是否可以组合“两个查询与聚合和分组依据”的（结果集）？

Question

1

Select id,count(*) as totalX FROM my_table WHERE x_factor = 1 GROUP BY id

结果集：

 id        totalX
 --------- --------------
         9             34
        10              6
        11             21
        12              3  

2

Select id,count(*) as totalY FROM my_table WHERE y_factor = 1 GROUP BY id

结果集 2：

 id        totalY
 --------- --------------
         9             334
        10              56
        11             251
        12              93 

有没有办法可以做到这一点：

 id        totalX        totalY         
 --------- --------------  --------------  
         9             34              334 
        10              6               56 
        11             21              251 
        12              3               93 

我想要 RHEL 5 上的 Sybase 12.5 解决方案，我也想知道这在任何其他数据库系统中是否可行。

---感谢您的回答--

Comparing EXECUTION TIME: (For a certain query) 
 Query 1:
Execution Time 61.
SQL Server cpu time: 6100 ms.  SQL Server elapsed time: 12133 ms.

Query 2:
Execution Time 53.
SQL Server cpu time: 5300 ms.  SQL Server elapsed time: 12090 ms.

Query X(1+2):
Execution Time 84.
SQL Server cpu time: 8400 ms.  SQL Server elapsed time: 21456 ms.

Answer 1

通过对列使用 CASE/WHEN 并根据真/假对 1 或 0 求和，您可以在同一个查询中获得两者...此外，如果您想要另一个值的总和，您可以做同样的事情列...只需将其替换为真实值而不是 1。

select 
      id,
      sum( CASE WHEN x_factor = 1 THEN 1 ELSE 0 END ) as X_Count, 
      sum( CASE WHEN y_factor = 1 THEN 1 ELSE 0 END ) as Y_Count
  from
      yourTable
  group by
      id

Answer 2

CASE ... {0|1} 对人们来说是一个很好的技巧，但我认为问题可能比这更简单。你有没有尝试过：

SELECT id, COUNT(x_factor) AS count_x, COUNT(y_factor) AS count_y FROM my_table GROUP BY id

Answer 3

这应该有效：

SELECT id, 
       sum(case when x_factor = 1 then 1 else 0 end) as totalX,
       sum(case when y_factor = 1 then 1 else 0 end) as totalY
    FROM my_table 
    WHERE x_factor = 1 
        OR y_factor = 1
    GROUP BY id