Question

我有以下查询：

with TEMPRESULT AS 
(
    select CONTACTS.line_id , count(*) totalcount
    from CONTACTS
    where (((E_DATE-S_DATE)*24*60*60)<=60 and to_char(S_DATE,'YYYY-MM-DD')='2015-12-12') 
    group by CONTACTS.line_id
    order by totalcount DESC
)

我想 TEMPRESULT 只保留select返回的前三行，怎么做？

Answer 1

您可以在rownum上指定条件：

with TEMPRESULT AS 
(
    select * from 
    (
      select CONTACTS.line_id , count(*) totalcount
      from CONTACTS
      where (((E_DATE-S_DATE)*24*60*60)<=60 and to_char(S_DATE,'YYYY-MM-DD')='2015-12-12') 
      group by CONTACTS.line_id
      order by totalcount DESC
    ) x
    where rownum < 3
)

Answer 2

如果你有oracle 12c，你可以先使用fetch

WITH TEMPRESULT AS
  (SELECT CONTACTS.line_id ,
    COUNT(*) totalcount
  FROM CONTACTS
  WHERE (((E_DATE-S_DATE)*24*60*60)<=60
  AND TO_CHAR(S_DATE,'YYYY-MM-DD')  ='2015-12-12')
  GROUP BY CONTACTS.line_id
  ORDER BY 2 DESC
  FETCH FIRST 3 rows only
  )
SELECT * FROM tempresult

获取前三行：with子句

2 个答案: