请教这样一个统计SQL应该怎么写？？谢谢

Question

select to_char(a,'yyyy-mm-dd hh24'),count(b) from tablename group by to_char(a,'yyyy-mm-dd hh24');

Answer 1

改成这样试试
Group by  trunc(a,'hh24')

Answer 2

我不明白为什么不能得到？ 你按照 GROUP BY TO_CHAR(A,'YYYY/MM/DD 24HH')

Answer 3

用count(*)比较合适：
SQL> select * from test3;        ID DOCTIME           P1 NEWZYZ               ZYZ1
---------- --------- ---------- -------------------- ----------
         6 01-JUL-01        222 2002-01-01
        22 01-JUL-01            1999-01-01
        22 01-JUL-01            2000-01-01
        83 24-SEP-02            asd                  sdf
        83 24-SEP-02            adfsd                dfsdf
        83 24-SEP-02            asd%df               dsfdsf%
         6 01-JUL-01        222 2002-01-01
        22 01-JUL-01            2001-01-018 rows selected.SQL> select to_char(doctime,'yyy-mm-dd hh24'),count(p1) from test3 group by to_c
har(doctime,'yyy-mm-dd hh24');TO_CHAR(DOCTIME,'YYY-MM-  COUNT(P1)
------------------------ ----------
001-07-01 00                      2
002-09-24 14                      0
002-09-24 15                      0SQL> select to_char(doctime,'yyy-mm-dd hh24'),count(*) from test3 group by to_ch
ar(doctime,'yyy-mm-dd hh24');TO_CHAR(DOCTIME,'YYY-MM-   COUNT(*)
------------------------ ----------
001-07-01 00                      5
002-09-24 14                      2
002-09-24 15                      1