CREATE TABLE salaryByMonth
(
 employeeNo vArchar2(20),
 yearMonth VARchar2(6),
 salary number
) ;
insert into SALARYBYMONTH (EMPLOYEENO, YEARMONTH, SALARY)
values (1, '200805', 500);
insert into SALARYBYMONTH (EMPLOYEENO, YEARMONTH, SALARY)
values (1, '200802', 150);
insert into SALARYBYMONTH (EMPLOYEENO, YEARMONTH, SALARY)
values (1, '200803', 200);
insert into SALARYBYMONTH (EMPLOYEENO, YEARMONTH, SALARY)
values (1, '200804', 300);
insert into SALARYBYMONTH (EMPLOYEENO, YEARMONTH, SALARY)
values (1, '200708', 100);
commIT;

SELECT EMPLOYEENO
      ,YEARMONTH
      ,SALARY
      ,MIN(SALARY) KEEP(DENSE_RANK First ORDER BY YEARMONTH) OVER(PARTITION BY EMPLOYEENO) FIRST_SALARY -- 基比分析 salary/first_salary
      ,LAG(SALARY, 1, 0) OVER(PARTITION BY EMPLOYEENO ORDER BY YEARMONTH) AS Prev_SAL -- 环比分析，与上个月份进行比较
      ,LAG(SALARY, 12, 0) OVER(PARTITION BY EMPLOYEENO ORDER BY YEARMONTH) AS PREV_12_SAL -- 同比分析，与上个年度相同月份进行比较   
      ,SUM(SALARY) OVER(PARTITION BY EMPLOYEENO, SubSTR(YEARMONTH, 1, 4) ORDER BY YEARMONTH RANGE UNBOUNDED PRECEDING) LJ --累计值
  From SALARYBYMONTH
 ORDER BY EMPLOYEENO
         ,YEARMONTH