【oracle】oracle 常用日期操作

1. 简单查询

说明	查询 sql
日期格式化	select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
本月第一天	select to_char(trunc(sysdate, 'mm'),'yyyy-mm-dd') from dual;
本月最后一天	select to_char(last_day(trunc(sysdate)),'yyyy-mm-dd') from dual;
上月第一天	select to_char(last_day(add_months(trunc(sysdate),-2))+1,'yyyy-mm-dd') from dual;
上月最后一天	select to_char(last_day(add_months(trunc(sysdate),-1)),'yyyy-mm-dd') from dual;
下月第一天	SELECT to_char(last_day(SYSDATE) + 1,'yyyy-mm-dd') FROM dual;
下月最后一天	select to_char(last_day(add_months(trunc(sysdate),1)),'yyyy-mm-dd') from dual;

2. 查询两个日期范围内所有日期列表

WITH xrange AS ( SELECT 
			to_date( '2025-05-03', 'yyyy-mm-dd' ) AS start_date, 
			to_date( '2025-06-07', 'yyyy-mm-dd' ) AS end_date 
			FROM dual ) 
SELECT
	t.GEN_DATE AS start_date,-- 开始时间
	t.GEN_DATE AS end_date -- 结束时间
FROM
	( SELECT to_char( start_date + LEVEL - 1, 'YYYYMMDD' ) AS gen_date FROM xrange CONNECT BY start_date + LEVEL - 1 <= end_date ) t;

3. 查询两个月份范围内所有月份列表

WITH xrange AS ( SELECT 
	to_date( '2024-01' || '-01', 'yyyy-mm-dd' ) AS start_date, 
	to_date( '2025-03' || '-01', 'yyyy-mm-dd' ) AS end_date FROM dual ) 
SELECT
	t.GEN_DATE AS start_month,-- 开始时间
	t.GEN_DATE AS end_month -- 结束时间
FROM
	(
	SELECT
		to_char( ADD_MONTHS( start_date, LEVEL - 1 ), 'YYYYMM' ) AS gen_date 
	FROM
		xrange CONNECT BY LEVEL <= MONTHS_BETWEEN( TRUNC( end_date, 'MONTH' ), TRUNC( start_date, 'MONTH' ) ) + 1 
	) t;

4. 查询指定月份的所有日期列表

WITH xrange AS (
	SELECT
		to_date( '202501' || '01', 'yyyymmdd' ) AS start_date,
		last_day( to_date( '202501' || '01', 'yyyymmdd' ) ) AS end_date 
	FROM
		dual 
	) SELECT
	t.GEN_DATE AS start_date,-- 开始时间
	t.GEN_DATE AS end_date -- 结束时间
FROM
	( SELECT to_char( start_date + LEVEL - 1, 'YYYYMMDD' ) AS gen_date FROM xrange CONNECT BY start_date + LEVEL - 1 <= end_date ) t;