SQL分組

一個SQL[@more@]SELECT rn,COUNT(*) FROM
(SELECT t.Phone, t.Create_Date, b.Rn, b.y_Date
FROM Yzqj4_Molog t,
(SELECT Ceil(Rownum / 30) Rn,
To_Date('2007-08-06 00:00', 'yyyy-MM-dd HH24:mi') +
(Rownum - 1) / 24 / 60 y_Date
FROM Yzqj4_Molog t
WHERE Rownum <= 1 * 24 * 60) b
WHERE To_Char(t.Create_Date, 'yyyy-mm-dd hh24:mi') =
To_Char(b.y_Date, 'yyyy-mm-dd hh24:mi')
AND Cid = '2301'
AND Create_Date > To_Date('2007-08-06 00:00:00', 'yyyy-MM-dd HH24:mi:ss')
AND Create_Date < To_Date('2007-08-07 00:00:00', 'yyyy-MM-dd HH24:mi:ss')) GROUP BY rn;