Oracle mostra tutti i dipendenti con più del salario medio di loro reparto
Domanda
Sto scrivendo una query per trovare i dipendenti che guadagnano maggiore del salario medio nel loro reparto. Ho bisogno di visualizzare l'ID del dipendente, stipendio, ID di divisione, e lo stipendio medio di tale reparto.
Ho una domanda che solo quasi funziona ma continua a darmi "ORA-00904: 'AVG_SAL': identificatore non valido" errori. Sto facendo questo in modo corretto. Perché mi appare questo errore identificativo valido?
SELECT employee_id, salary, department_id,
(SELECT ROUND(AVG(salary),2)
FROM employees e_inner
WHERE e_inner.department_id = e.department_id) AS avg_sal
FROM employees e
WHERE salary > avg_sal
ORDER BY avg_sal DESC
Soluzione
Non credo che si possa fare riferimento a un alias di colonna (avg_sal in questo caso) in una clausola WHERE.
È necessario ripetere che query interna, cioè:.
SELECT employee_id, salary, department_id,
(SELECT ROUND(AVG(salary),2)
FROM employees e_inner
WHERE e_inner.department_id = e.department_id) AS avg_sal
FROM employees e
WHERE salary >
(SELECT ROUND(AVG(salary),2)
FROM employees e_inner
WHERE e_inner.department_id = e.department_id)
ORDER BY avg_sal DESC
Non è fantastico, con quei due domande interiori, ma questo è il modo più semplice, per correggere l'errore.
Aggiornamento: non hanno testato questo, ma provare quanto segue:
SELECT e.employee_id, e.salary, e.department_id, b.avg_sal
FROM employees e
INNER JOIN
(SELECT department_id, ROUND(AVG(salary),2) AS avg_sal
FROM employees
GROUP BY department_id) e_avg ON e.department_id = e_avg.department_id AND e.salary > e_avg.avg_sal
ORDER BY e_avg.avg_sal DESC
Altri suggerimenti
più efficiente utilizzare Analytics:
select employee_id, salary, department_id, avg_sal
from
(
SELECT employee_id, salary, department_id,
round(avg(salary) over (partition by department_id), 2) avg_sal
from emp
)
where salary > avg_sal
order by avg_sal desc
Si potrebbe riscrivere come un join:
SELECT e1.employee_id
, e1.salary
, e1.department_id
, ROUND(AVG(e2.salary),2) as Avg_Sal
FROM employees e
JOIN employees e2
ON e2.department_id = e.department_id
GROUP BY
e1.employee_id
, e1.salary
, e1.department_id
HAVING e1.salary > ROUND(AVG(e2.salary),2)
O una subquery:
SELECT *
FROM (
SELECT employee_id
, salary
, department_id
, (
SELECT ROUND(AVG(salary),2)
FROM employees e_inner
WHERE e_inner.department_id = e.department_id
) AS avg_sal
FROM employees e
) as SubqueryAlias
WHERE salary > avg_sal
select *
from employees e
join(
select Round(avg(salary)) AvgSal,department_id,department_name as dept_name
from employees join departments
using (department_id)
group by department_id,department_name
) dd
using(department_id)
where e.salary > dd.AvgSal;
un'altra soluzione
select *
from employees e,
(
select
department_id,
avg(salary) avg_sal
from employees
group by department_id
) e1
where e.department_id=e1.department_id
and e.salary > e1.avg_sal