在一个SQL查询中加入两个COUNT()

Question

我有以下Oracle SQL查询:

SELECT ST.hrs_source_id, 
       TT.hrs_source_name, 
       Count(*) 
FROM   ps_hrs_app_profile P, 
       ps_hrs_rcmnt_sts S, 
       ps_hrs_al_log_srce ST, 
       ps_hrs_source TT 
WHERE  ST.hrs_source_id = TT.hrs_source_id 
       AND P.hrs_person_id = S.hrs_person_id 
       AND P.hrs_al_log_id = ST.hrs_al_log_id 
       AND S.status_code = '010' 
       AND S.status_dt BETWEEN '01-JAN-09' AND '31-MAR-16' 
GROUP  BY ST.hrs_source_id, 
          TT.hrs_source_name 
ORDER  BY TT.hrs_source_name ASC; 

上面的查询产生的结果以3列:HRS_SOURCE_ID,HRS_SOURCE_NAME,COUNT.但我想将两个COUNTs加入一个查询中.第二个查询与上面相同,但只STATUS_CODE应该等于'060',而在第一个查询中它等于'010'.如何COUNT在一个Query中将两个s连接在一起,总共将有4列？请帮忙解决.

Answer 1

您可以使用案例表达式来获取不同的计数:

SELECT ST.HRS_SOURCE_ID, 
       TT.HRS_SOURCE_NAME, 
       COUNT(case when S.STATUS_CODE = '060' then 1 end) as cnt60, 
       count(case when S.STATUS_CODE = '010' then 1 end) as cnt10
FROM PS_HRS_APP_PROFILE P, PS_HRS_RCMNT_STS S, PS_HRS_AL_LOG_SRCE ST, PS_HRS_SOURCE TT
WHERE ST.HRS_SOURCE_ID = TT.HRS_SOURCE_ID
   AND P.HRS_PERSON_ID = S.HRS_PERSON_ID
   AND P.HRS_AL_LOG_ID = ST.HRS_AL_LOG_ID
   AND (S.STATUS_CODE = '010' or S.STATUS_CODE = '060')
   AND S.STATUS_DT BETWEEN '01-JAN-09' AND '31-MAR-16'
GROUP BY ST.HRS_SOURCE_ID, TT.HRS_SOURCE_NAME
ORDER BY TT.HRS_SOURCE_NAME ASC

注意where子句中的OR.

您可以更好地理解与计数相结合的总和:

sum(case when S.STATUS_CODE = '060' then 1 else 0 end) cnt60

为了解释查询中的情况,没有else.如果status与060不同,则case返回的值为null.Null不计算在内count.