# Oracle SQL Date calculate ###### tags: `Database` `Oracle` `SQL` ## This month first day ```SQL SELECT TRUNC(sysdate,'mm') FROM dual ``` ## This month last day ```SQL SELECT LAST_DAY(TRUNC(sysdate,'mm')) FROM dual ``` ## This year frist day ```SQL SELECT TRUNC(sysdate,'yyyy') FROM dual ``` ## Previous year today ```SQL SELECT ADD_MONTHS(sysdate,-12) FROM dual ```