Question

我有一个表格，我希望通过orig调用和term调用将其生成一行组。我会计算它有多少次传入和传出......这是表格

致电

|ID | originating call |   terminating call |  call type    
| 1 | 123              |       123          |  incoming
| 2 | 123              |       123          |  outgoing
| 3 | 123              |       321          |  incoming
| 4 | 123              |       321          |  incoming

结果应该是

 originating call |   terminating call |  incoming  | outgoing
      123         |       123          |     1      |    1
      123         |       321          |     2      |    0

我已尝试将计数（）作为传入计数（）作为传出，但我不知道接下来应该做什么。我应该通过发起呼叫和终止呼叫对其进行分组吗？

Answer 1

这称为条件聚合。您可以使用case语句执行基本查询：

select originating, terminating,
       sum(case when calltype = 'incoming' then 1 else 0 end) as incoming,
       sum(case when calltype = 'outgoing' then 1 else 0 end) as outgoing,
from calltable ct
group by originating, terminating;

这适用于所有数据库。要使id列在数据库之间有所不同。在SQL Server中，您可以这样做：

select row_number() over (order by (select NULL)) as id,
       originating, terminating,
       sum(case when calltype = 'incoming' then 1 else 0 end) as incoming,
       sum(case when calltype = 'outgoing' then 1 else 0 end) as outgoing,
from calltable ct
group by originating, terminating;

在MySQL中，你会得到id：

select @id := @id + 1 as id,
       originating, terminating,
       sum(calltype = 'incoming') as incoming,
       sum(calltype = 'outgoing') as outgoing,
from calltable ct cross join
     (select @id := 0) const
group by originating, terminating;

尽管case在MySQL中工作正常，但这个版本使用的是在这种情况下很方便的简写。

Answer 2

使用以下查询：

select originating, terminating,
       sum(case when calltype ='incoming' then 1 else 0 end) as incoming,
       sum(case when calltype ='outgoing' then 1 else 0 end) as outgoing,
from Table_Name

分组来源，终止;

搜索查询计算两个字段，结果为1行组

2 个答案: