oracle日期相关函数

1、查询上月的所有日期：

SELECT TO_CHAR (Trunc (Trunc (SYSDATE,'MM') - 1,'month') + LEVEL - 1,'yyyy-MM-dd') AS month_day FROM DUAL CONNECT BY LEVEL <= TO_CHAR (LAST_DAY (Trunc (SYSDATE,'MM') - 1),'dd');

2、查询当月的所有日期：

SELECT TO_CHAR (Trunc (SYSDATE,'dd');

3、查询上月月份：

SELECT TO_CHAR(ADD_MONTHS(SYSDATE,-1),'YYYY-MM') FROM DUAL;

4、查询当月天数：

SELECT TO_CHAR (LAST_DAY (Trunc (SYSDATE,'mm')),'DD') mounth_count FROM DUAL;

5、查询当月第一天：

SELECT Trunc (SYSDATE,'month') FROM DUAL;

6、查询当月最后一天：

SELECT TO_CHAR (LAST_DAY (SYSDATE),'YYYY-MM-DD') FROM DUAL;

7、计算两个日期之间天数：

SELECT TO_DATE ('2013-08-05','yyyy-MM-dd') - TO_DATE ('2013-08-01','yyyy-MM-dd') + 1 AS count_day FROM DUAL;

8、查询两个日期之间的所有日期：

SELECT ROWNUM,TO_DATE ('2013-01-02','yyyy-MM-dd') + ROWNUM - 1 AS allday FROM DUAL CONNECT BY ROWNUM < TO_DATE ('2013-01-07','yyyy-MM-dd') - TO_DATE ('2013-01-02','yyyy-MM-dd') + 2;

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