PL/SQL Fifth ORDER by sort

1 --Sort2 --1. Sort by list3 --2. Sort aliases4 --3, column position sorting (when using Union,union All,intersect,minus collection operation, the list is different, but want to sort)5 SELECTDeptno,dname fromDeptUNION6 SELECTEmpno,ename fromEMP7 ORDER  by 1 DESC;8 --4. Sorting using non-select columns9 SELECTEname fromEmpORDER  bySalDESC;Ten --5, multi-line sorting, first based on the ORDER BY clause of the first column sort, if the value of the first column is the same, sorted based on the second column, and so on

PL/SQL Fifth ORDER by sort