小编Bri*_*ock的帖子

我看过其他类似的问题，它们似乎与我想要做的有点不同。

我有一个查询，我在其中选择两个计数值，我想将一个除以另一个。

这是我的工作代码：

SELECT (SELECT count(DISTINCT s.lastfirst) 
          FROM students s
          JOIN cc ON s.id = cc.studentid
          JOIN courses c on cc.course_number = c.course_number
         WHERE cc.schoolid='109'
           AND c.course_name LIKE 'AP %' 
           AND substr(cc.termid,0,1) <> '-'
           AND cc.dateenrolled BETWEEN to_date('08/01/2010','MM/DD/YYYY') AND  
               to_date('08/01/2011','MM/DD/YYYY')) as AP, 
       (SELECT count(DISTINCT s.lastfirst) 
          FROM students s
          JOIN cc ON s.id = cc.studentid
          JOIN courses c on cc.course_number = c.course_number
         WHERE cc.schoolid = '109'
           AND substr(cc.termid,0,1) <> '-'
           AND cc.dateenrolled BETWEEN to_date('08/01/2010','MM/DD/YYYY') 
           AND to_date('08/01/2011','MM/DD/YYYY')) as ttl
 FROM DUAL

这是我打破它的地方： …