oracle 取日期字段的年月日。

-- Create table
create table ODC_OPERATION_RECORD
(
  ID               NUMBER,
  OPERATOR         VARCHAR2(100),
  OPERATION_DATE   DATE,
  OPERATION_NAME   VARCHAR2(100),
  OPERATION_NUMBER INTEGER,
  REMARK           VARCHAR2(200)
)
tablespace ODC_DATA
  pctfree 10
  initrans 1
  maxtrans 255
  storage
  (
    initial 64K
    next 1M
    minextents 1
    maxextents unlimited
  );
-- Add comments to the columns 
comment on column ODC_OPERATION_RECORD.ID
  is '唯一标识id';
comment on column ODC_OPERATION_RECORD.OPERATOR
  is '操作员';
comment on column ODC_OPERATION_RECORD.OPERATION_DATE
  is '操作日期';
comment on column ODC_OPERATION_RECORD.OPERATION_NAME
  is '操作名称';
comment on column ODC_OPERATION_RECORD.OPERATION_NUMBER
  is '操作条数';
comment on column ODC_OPERATION_RECORD.REMARK
  is '备注';

SELECT TO_CHAR(RE.OPERATION_DATE, 'YYYY') || '.' ||
       TO_CHAR(RE.OPERATION_DATE, 'MM') YEAR_MONTH,
       --TO_CHAR(RE.OPERATION_DATE, 'DD') DAY,
       RE.OPERATION_NAME,
       COUNT(RE.OPERATION_NAME),
       SUM(RE.OPERATION_NUMBER)
  FROM ODC_OPERATION_RECORD RE
 GROUP BY TO_CHAR(RE.OPERATION_DATE, 'YYYY') || '.' ||
          TO_CHAR(RE.OPERATION_DATE, 'MM'),
          RE.OPERATION_NAME;