如何使用条件计算 SQL (Oracle) 中的多个列？

Question

我正在开发 SMS-Gateway，它拥有多个不同号码的收费 SMS-服务，
每条发送给客户的短信都有以下 4 种状态（已转发、已送达、已过期、送达失败）

现在我有以下充电系统的 first_table 以及以下详细信息（TABLE-A）

及以下 (TABLE-B) 包含每条已发送 SMS 的状态及其 ID

以下是我预期的最终结果，用于预测每个短信服务的详细信息：

起初我认为这很简单，我只需要使用COUNT(Case when ...)
但就我而言，我有数千个短信号码（服务），所以如果我使用这种方法，它会是这样的：-

COUNT(CASE WHEN a.SMS_SHORT_CODE='1111' AND B.STATUS='forwarded' )
COUNT(CASE WHEN a.SMS_SHORT_CODE='1111' AND B.STATUS='delivered' )
COUNT(CASE WHEN a.SMS_SHORT_CODE='1111' AND B.STATUS='expired' )
COUNT(CASE WHEN a.SMS_SHORT_CODE='1111' AND B.STATUS='delivery failed' )
COUNT(CASE WHEN a.SMS_SHORT_CODE='5000' AND B.STATUS='forwarded' )
COUNT(CASE WHEN a.SMS_SHORT_CODE='5000' AND B.STATUS='delivered' )
COUNT(CASE WHEN a.SMS_SHORT_CODE='5000' AND B.STATUS='expired' )
COUNT(CASE WHEN a.SMS_SHORT_CODE='5000' AND B.STATUS='delivery failed' )
...
...
...
...
...
...
...

当您有许多服务还注意到CASE 只能处理 250 个条件时，上述方法不实用？

那么，使用 SMS-ID 对（表 B）上的（表 A）执行left outer join 并计算每个 SMS 状态并进行如下预测的最佳方法是什么？

Answer 1

我建议条件聚合：

select b.SMS_SHORT_CODE,
       sum(case when status = 'forwaded' then 1 else 0 end) as count_of_forwaded,
       sum(case when status = 'delivered' then 1 else 0 end) as count_of_status,
       sum(case when status = 'expired' then 1 else 0 end) as count_of_expired,
       sum(case when status = 'delivery failed' then 1 else 0 end) as count_of_delivery_failed
from TABLEB b
group by b.SMS_SHORT_CODE ;

请注意，不需要JOIN。您要汇总的所有数据都在TABLEB。

Answer 2

请使用以下查询，

select 
A.SMS_SHORT_CODE,
case when status = 'forwaded' then count(status ) end as count_of_forwaded,
case when status = 'delivered' then count(status ) end as count_of_status,
case when status = 'expired' then count(status ) end as count_of_expired,
case when status = 'delivery failed' then count(status ) end as count_of_delivery_failed
from TABLEA A
inner join TABLEB B 
on (A.SMS_ID = B.SMS_ID)
group by A.SMS_SHORT_CODE, status ;

Answer 3

您可以对那些status 列使用PIVOT 子句（在Oracle 11g 版本中引入）：

SELECT sms_short_code, 
       COUNT_OF_forwarded, 
       COUNT_OF_delivered, 
       COUNT_OF_expired,
       COUNT_OF_delivery_failed
  FROM tableB
 PIVOT 
 (
  COUNT(*) FOR status IN ( 'forwarded'       AS COUNT_OF_forwarded,
                           'delivered'       AS COUNT_OF_delivered,
                           'expired'         AS COUNT_OF_expired,
                           'delivery failed' AS COUNT_OF_delivery_failed )
 ) 

例如只用TableB就够了。

Demo