orale 查询每年、每月、每日统计量的sql语句

每年

select to_char(createtime, 'YYYY') 年, count(*) from table  group by to_char(createtime, 'YYYY');

每季度

select to_char(createtime, 'q') 年, count(*) from table  group by to_char(createtime, 'q');

每月

select to_char(createtime, 'YYYY') 年, to_char(createtime, 'mm') 月, count(*) from table  group by to_char(createtime, 'YYYY'), to_char(createtime, 'mm');

每日

select to_char(createtime, 'YYYY') 年,to_char(createtime, 'mm') 月,to_char(createtime, 'dd') 日, count(*) from table group by to_char(createtime, 'YYYY'), to_char(createtime, 'mm'),to_char(createtime, 'dd');

当中createtime为date类型。假设为varchar先要转换为date类型