[Oracle] months_between

若我想知道兩個日期間差幾個月，可運用 months_between 此內建 function 來完成，若要做四捨五入，可加上 round function；若要做無條件進位，可加上 ceil function。

範例如下：

select months_between(to_date('20200901', 'YYYYMMDD'), TO_DATE('20200722', 'YYYYMMDD'))        as VAL1,
       round(months_between(to_date('20200901', 'YYYYMMDD'), TO_DATE('20200722', 'YYYYMMDD'))) as VAL2,
       ceil(months_between(to_date('20200901', 'YYYYMMDD'), TO_DATE('20200722', 'YYYYMMDD')))  as VAL3
from dual;

執行結果如下：

Reference

[1] https://www.w3resource.com/oracle/datetime-functions/oracle-months_between-function.php