Oracle技术总结

获取某个时间段的年份

SELECT TO_CHAR(ADD_MONTHS(TO_DATE(‘2010’, ‘yyyy’), (ROWNUM - 1) * 12), ‘yyyy’) as year
FROM DUAL
CONNECT BY ROWNUM <= months_between(to_date(‘2019’, ‘yyyy’), to_date(‘2010’, ‘yyyy’)) / 12 + 1

to_char用法
用作日期转换：

to_char(date,'格式');

select to_date('2005-01-01 ','yyyy-MM-dd') from dual;
select to_char(sysdate,'yyyy-MM-dd HH24:mi:ss') from dual;`在这里插入代码片`

（2）处理数字：

to_char(number,'格式');

select to_char(88877) from dual;
select to_char(1234567890,'099999999999999')  from dual;
select to_char(12345678,'999,999,999,999')  from dual;
select to_char(123456,'99.999')  from dual;
select to_char(1234567890,'999,999,999,999.9999')  from dual;

（3）to_char(salary,’$99,99’);

select TO_CHAR(123,'$99,999.9') from dual;

（4）用于进制转换：将10进制转换为16进制；

select to_char(4567,'xxxx') from dual;
select to_char(123,'xxx') from dual;