使用 Oracle 中的子查询分组的值有条件地更新表

Question

问题是，将参与过 5 个或 5 个以上项目的所有员工的工资更新为 50%，更新为 30%（>= 3 个项目），更新为 20%（>= 1 个项目），项目数量为通过对 EMPLOYEE_PROJECT_HISTORY 执行分组查询得到；

我已经尝试过这些查询

update emp set emp.sal=
case 
when jemp.pcount >=5 then emp.sal+ (emp.sal*50)/100
when jemp.pcount >=3 then emp.sal+ (emp.sal*30)/100
when jemp.pcount >=1 then emp.sal+ (emp.sal*20)/100
else emp.sal+ (emp.sal*20)/100
end 
from employee emp join (select empno as jempno,count(projectno) as pcount from EMPLOYEE_PROJECT_HISTORY by empno) jemp on emp.empno=jemp.jempno ;

update employee a set a.sal= case (select count(b.projectno) as pcount from EMPLOYEE_PROJECT_HISTORY b group by b.empno ) 
    when b.pcount >5 then
    a.sal = a.sal+ (a.sal*50)/100
    when pcount >3 then
    a.sal = a.sal+ (a.sal*30)/100
    when pcount >1 then
    a.sal = a.sal+ (a.sal*20)/100
    end;

Answer 1

如果 Oracle 中的联接包含 GROUP BY 子句，您将无法更新该联接。您可以使用内联子查询，如下所示：

UPDATE employee e
   SET sal = sal * (SELECT CASE
                              WHEN COUNT(*) >= 5 THEN
                               1.5
                              WHEN COUNT(*) >= 3 THEN
                               1.3
                              WHEN COUNT(*) >= 1 THEN
                               1.2
                              ELSE
                               1
                           END
                      FROM employee_project_history eph
                     WHERE eph.empno = e.empno);