sql ,groupby分组后显示几列数据，
SELECT T.DEP_ID, to_char(trunc(to_date(t.option_time,'yyyy-mm-dd hh24:mi:ss'),'dd'),'yyyymmdd'),NVL(COUNT(T.OPTION_ID),0) AS ADDCOUNT
FROM MST_USER_OPTION T
WHERE T.OPTION_FLG != 0
GROUP BY T.DEP_ID,to_char(trunc(to_date(t.option_time,'yyyy-mm-dd hh24:mi:ss'),'dd'),'yyyymmdd')
ORDER BY ADDCOUNT
trunc是截断数据，把日期截断成了，天相等的， 防止天和groupby T.DEP_ID 发生冲突.
FROM MST_USER_OPTION T
WHERE T.OPTION_FLG != 0
GROUP BY T.DEP_ID,to_char(trunc(to_date(t.option_time,'yyyy-mm-dd hh24:mi:ss'),'dd'),'yyyymmdd')
ORDER BY ADDCOUNT
trunc是截断数据，把日期截断成了，天相等的， 防止天和groupby T.DEP_ID 发生冲突.