Diferència entre revisions de la pàgina «M2 - Bases de dades / Exercicis UF2: Llenguatges SQL / Solucions Repàs consultes HR»
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==Solucions Repàs Consultes BBDD HR== | ==Solucions Repàs Consultes BBDD HR== | ||
+ | 1) Muestra los departamentos (departament_id) en los que sus empleados tienen un salario superior a todos los empleados de otro departamento. | ||
+ | <pre> | ||
+ | SELECT department_id | ||
+ | FROM employees | ||
+ | WHERE department_id IS NOT NULL | ||
+ | GROUP BY department_id | ||
+ | HAVING min(salary) > ANY (SELECT max(salary) | ||
+ | FROM employees | ||
+ | GROUP BY department_id); | ||
+ | </pre> | ||
− | 1. Muestra el nombre, apellido i salario mensual de los empleados que cobren mas que Jennifer ordenado por salario descendiente | + | 2) Igual que 1, pero mostrando también el nombre del departamento. |
+ | <pre> | ||
+ | SELECT department_id, d.department_name | ||
+ | FROM employees e JOIN departments d | ||
+ | USING (department_id) | ||
+ | WHERE department_id IS NOT NULL | ||
+ | GROUP BY department_id, d.department_name | ||
+ | HAVING min(salary) > ANY (SELECT max(salary) | ||
+ | FROM employees | ||
+ | GROUP BY department_id); | ||
+ | </pre> | ||
+ | |||
+ | 3) Igual que 1 pero mostrando los nombres de los empleados. | ||
+ | <pre> | ||
+ | SELECT first_name, last_name, department_id | ||
+ | FROM employees | ||
+ | WHERE department_ID in (SELECT department_id | ||
+ | FROM employees | ||
+ | WHERE department_id IS NOT NULL | ||
+ | GROUP BY department_id | ||
+ | HAVING min(salary) > ANY (SELECT max(salary) | ||
+ | FROM employees | ||
+ | GROUP BY department_id)); | ||
+ | </pre> | ||
+ | |||
+ | 4)Muestra id, last_name, salary i la media de salarios del departamento de su departamento para todos aquellos empleados que ganen más que la media de su departamento. | ||
+ | <pre> | ||
+ | SELECT employee_id, last_name, salary, average.avgsalary | ||
+ | FROM employees NATURAL JOIN (SELECT department_id, trunc(AVG(salary)) avgsalary | ||
+ | FROM employees | ||
+ | GROUP BY department_id) average | ||
+ | WHERE salary > average.avgsalary; | ||
+ | </pre> | ||
+ | |||
+ | 5) Muestra id, first_name, last_name y hire_date de los 10 empleados más antiguos de la empresa. | ||
+ | <pre> | ||
+ | SELECT rownum, first_name, last_name, hire_date | ||
+ | FROM (SELECT first_name, last_name, hire_date | ||
+ | FROM employees | ||
+ | ORDER BY hire_date) | ||
+ | WHERE rownum <=10; | ||
+ | </pre> | ||
+ | |||
+ | 6) Muestra id, first_name, last_name, nombre del departamento y salario de los 5 empleados mejor pagagados de la empresa. | ||
+ | <pre> | ||
+ | SELECT rownum, first_name, last_name, salary, department_name | ||
+ | FROM (SELECT first_name, last_name, salary, department_id | ||
+ | FROM employees | ||
+ | ORDER BY salary DESC) JOIN departments USING(department_id) | ||
+ | WHERE rownum <=5; | ||
+ | </pre> | ||
+ | <!-- | ||
+ | NO!7) Muestra la estructura jerárquica de la empresa identando los diferentes niveles. | ||
+ | <pre> | ||
+ | select concat(lpad(' ', level * 3 - 3), last_name) nombre | ||
+ | from employees | ||
+ | connect by prior employee_id = manager_id | ||
+ | start with manager_id is null; | ||
+ | </pre> | ||
+ | |||
+ | NO!8) Muestra los costes totales de los salarios por departamento y oficio. Deben aparacer los registros. | ||
+ | <pre> | ||
+ | SELECT department_id, job_id, SUM(salary) | ||
+ | FROM employees | ||
+ | GROUP BY ROLLUP (department_id,job_id); | ||
+ | </pre> | ||
+ | |||
+ | NO!9) Igual que 8 pero que aparezca también los costes en función del manager. | ||
+ | <pre> | ||
+ | SELECT department_id, job_id, manager_id, SUM(salary) | ||
+ | FROM employees | ||
+ | GROUP BY ROLLUP ((department_id,job_id),(manager_id)); | ||
+ | </pre> | ||
+ | |||
+ | NO!10) Muestra los costes totales de los salarios por departamento y oficio. Deben aparacer los registros y los subtotales relativos. | ||
+ | <pre> | ||
+ | SELECT department_id, job_id, SUM(salary) | ||
+ | FROM employees | ||
+ | GROUP BY CUBE (department_id,job_id); | ||
+ | </pre> | ||
+ | |||
+ | NO!11) Igual que la consulta 10, pero debe aparecer unas columnas adicionales (valores 1 o 0) indicando de que subtotal se trata. | ||
+ | <pre> | ||
+ | SELECT department_id, job_id, SUM(salary),GROUPING(department_id), GROUPING(job_id) | ||
+ | FROM employees | ||
+ | GROUP BY CUBE (department_id,job_id); | ||
+ | </pre> | ||
+ | --> | ||
+ | 12) Muestra el id, first_name, department_id, i salari del empleat(s) que guanyen més de cada departament. | ||
+ | <pre> | ||
+ | SELECT employee_id, first_name, department_id, salary | ||
+ | FROM employees NATURAL JOIN (SELECT department_id, MAX(salary) maxsal | ||
+ | FROM employees | ||
+ | GROUP BY department_id) MAXIMS | ||
+ | WHERE salary = MAXIMS.maxsal; | ||
+ | </pre> | ||
+ | <pre> | ||
+ | SELECT employee_id, first_name, department_id, salary | ||
+ | FROM employees e | ||
+ | WHERE salary = (SELECT MAX(salary) | ||
+ | FROM employees d | ||
+ | WHERE d.department_id= e.department_id); | ||
+ | </pre> | ||
+ | <pre> | ||
+ | SELECT employee_id, first_name, department_id, salary | ||
+ | FROM employees | ||
+ | WHERE (salary, department_id) IN (SELECT MAX(salary), department_id | ||
+ | FROM employees | ||
+ | GROUP BY department_id); | ||
+ | |||
+ | </pre> | ||
+ | <!-- | ||
+ | 13) Igual que 12, pero sustituyendo el department_id por el department_name. | ||
+ | <pre> | ||
+ | SELECT employee_id, first_name, department_name, salary | ||
+ | FROM employees NATURAL JOIN (SELECT department_id, MAX(salary) maxsal | ||
+ | FROM employees | ||
+ | GROUP BY department_id) MAXIMS | ||
+ | JOIN departments USING (department_id) | ||
+ | WHERE salary = MAXIMS.maxsal; | ||
+ | </pre> | ||
+ | |||
+ | 14) Quants departaments hi ha a cada país. Mostreu nom del país i nombre de departaments. | ||
+ | <pre> | ||
+ | SELECT c.country_name, count(department_id) | ||
+ | FROM countries c NATURAL JOIN locations NATURAL JOIN departments | ||
+ | GROUP BY c.country_name; | ||
+ | </pre> | ||
+ | |||
+ | 15) Quants empleats treballen a cada país. Mostreu nom del país i nombre de empleats. | ||
+ | <pre> | ||
+ | SELECT c.country_name, count(e.employee_id) | ||
+ | FROM countries c NATURAL JOIN locations l NATURAL JOIN departments | ||
+ | JOIN employees e USING (department_id) | ||
+ | GROUP BY c.country_name; | ||
+ | </pre> | ||
+ | |||
+ | 16) Mostreu el first_name i last_name, carreg i nom del departament dels 3 empleats que menys temps han estat fent una feina. | ||
+ | <pre> | ||
+ | SELECT * | ||
+ | FROM (SELECT first_name, last_name, j.job_id, department_name | ||
+ | FROM employees e JOIN job_history j USING (employee_id) | ||
+ | JOIN departments d ON (d.department_id= e.department_id) | ||
+ | ORDER BY j.end_date-j.start_date) | ||
+ | WHERE ROWNUM<=3; | ||
+ | </pre> | ||
+ | |||
+ | 17) Quants empleats de cada grau salarial hi ha a cada departament. Mostreu nom del departament, grau salarial i nombre de empleats. Ordenat per nom de departament i grau salarial. | ||
+ | <pre> | ||
+ | SELECT d.department_name, j.grade_level, COUNT(e.employee_id) | ||
+ | FROM departments d JOIN employees e USING(department_id) | ||
+ | JOIN job_grades j ON (e.salary BETWEEN j.lowest_sal AND j.highest_sal) | ||
+ | GROUP BY d.department_name, j.grade_level | ||
+ | ORDER BY d.department_name, j.grade_level; | ||
+ | </pre> | ||
+ | |||
+ | 18) Quin és l'ofici (job_title) amb un rang salarial més ampli. | ||
+ | <pre> | ||
+ | SELECT job_title | ||
+ | FROM jobs NATURAL JOIN employees | ||
+ | GROUP BY job_title | ||
+ | HAVING MAX(salary)-MIN(salary) = (SELECT MAX(MAX(salary)-MIN(salary)) | ||
+ | FROM employees | ||
+ | GROUP BY job_id); | ||
+ | </pre> | ||
+ | |||
+ | 19) Mostreu la següent sortida: | ||
+ | <pre> | ||
+ | SALARI I COMISSIO | ||
+ | ... | ||
+ | 44 RANDALL MATOS té un salari de $2,600.00 | ||
+ | 45 PETER VARGAS té un salari de $2,500.00 | ||
+ | 46 JOHN RUSSELL té un salari de $14,000.00, amb la comissió $19,600.00 | ||
+ | 47 KAREN PARTNERS té un salari de $13,500.00, amb la comissió $17,550.00 | ||
+ | ... | ||
+ | </pre> | ||
+ | <pre> | ||
+ | SELECT RPAD(UPPER(first_name) || ' ' || UPPER (last_name),18,' ') || ' tiene un salario de' || | ||
+ | TO_CHAR(salary, '$99,999.00') || NVL2(commission_pct,', amb la comissió' || | ||
+ | To_CHAR(salary * (1+commission_pct), '$99,999.00'),'') "SALARI I COMISSIO" | ||
+ | FROM employees; | ||
+ | </pre> | ||
+ | |||
+ | 20) Quants oficis diferents hi ha a cada departament. Mostreu nom del departament i nombre d'oficis. | ||
+ | <pre> | ||
+ | SELECT department_name "Nom Departament", COUNT(DISTINCT job_id) "Nombre Oficis" | ||
+ | FROM departments JOIN employees USING(department_id) | ||
+ | GROUP BY department_name; | ||
+ | </pre> | ||
+ | |||
+ | 21) Quants empleats hi ha a cada departament, quants cobren comissió i quants no la cobren. Mostreu el nom del departaments. Poseu alies de columnes adequats. | ||
+ | <pre> | ||
+ | SELECT department_name "Departament", COUNT(employee_id) "Empelats", | ||
+ | COUNT(employee_id)-COUNT(commission_pct) "Sense comissió", COUNT(commission_pct) "Amb comissió" | ||
+ | FROM employees JOIN departments USING(department_id) | ||
+ | GROUP BY department_name; | ||
+ | </pre> | ||
+ | |||
+ | 22) Quin cost en salaris, tenint en compte la comissió, té cada país. Mostreu el nom del país i el cost. | ||
+ | <pre> | ||
+ | SELECT country_name "Nom pais", SUM(salary*(1+NVL(commission_pct,0))) "Cost salarial" | ||
+ | FROM countries NATURAL JOIN locations NATURAL JOIN departments JOIN employees USING(department_id) | ||
+ | GROUP BY country_name; | ||
+ | </pre> | ||
+ | |||
+ | 23) Quin és el país que té un cost salarial més alt, tenint en compte la comissió. | ||
+ | <pre> | ||
+ | SELECT country_name "Nom pais" | ||
+ | FROM (SELECT country_name | ||
+ | FROM countries NATURAL JOIN locations NATURAL JOIN departments JOIN employees USING(department_id) | ||
+ | GROUP BY country_name | ||
+ | ORDER BY SUM(salary*(1+NVL(commission_pct,0))) DESC) | ||
+ | WHERE ROWNUM=1; | ||
+ | </pre> | ||
+ | |||
+ | 24) Quin són els tres països amb un cost salarial més alt, tenint en compte la comissió. | ||
+ | <pre> | ||
+ | SELECT country_name "Nom pais" | ||
+ | FROM (SELECT country_name | ||
+ | FROM countries NATURAL JOIN locations NATURAL JOIN departments JOIN employees USING(department_id) | ||
+ | GROUP BY country_name | ||
+ | ORDER BY SUM(salary*(1+NVL(commission_pct,0))) DESC) | ||
+ | WHERE ROWNUM<=3; | ||
+ | </pre> | ||
+ | |||
+ | |||
+ | 25) Mostreu el nom dels empleats, el nom del departament, els mesos sencers treballats i els dies, del historial (job_history). Ordenats de forma descendent per mesos i dies. | ||
+ | <pre> | ||
+ | Nom Departament Ofici Mesos Dies | ||
+ | -------- -------------- ------------------------ ------ ----- | ||
+ | Jennifer Administration Administration Assistant 69 2100 | ||
+ | Lex Executive Programmer 66 2018 | ||
+ | Jennifer Administration Public Accountant 53 1644 | ||
+ | ... | ||
+ | </pre> | ||
+ | <pre> | ||
+ | SELECT e.first_name "Nom", d.department_name "Department", j.job_title "Ofici", | ||
+ | Trunc(months_between(h.end_date,h.start_date)) "Mesos", h.end_date-h.start_date "Dies" | ||
+ | FROM job_history h JOIN employees e ON (h.employee_id=e.employee_id) | ||
+ | JOIN departments d ON(d.department_id=e.department_id) | ||
+ | JOIN jobs j ON (j.job_id = h.job_id) | ||
+ | ORDER BY 4 DESC, 5 DESC; | ||
+ | </pre> | ||
+ | 26) El mateix que el 25, però mostrant només els 5 que més temps han treballat. | ||
+ | <pre> | ||
+ | SELECT * | ||
+ | FROM (SELECT e.first_name "Nom", d.department_name "Department", j.job_title "Ofici", | ||
+ | Trunc(months_between(h.end_date,h.start_date)) "Mesos", h.end_date-h.start_date "Dies" | ||
+ | FROM job_history h JOIN employees e ON (h.employee_id=e.employee_id) | ||
+ | JOIN departments d ON(d.department_id=e.department_id) | ||
+ | JOIN jobs j ON (j.job_id = h.job_id) | ||
+ | ORDER BY 4 DESC, 5 DESC) | ||
+ | WHERE ROWNUM <= 5; | ||
+ | </pre> | ||
+ | |||
+ | 27) Muestra el nombre, apellido i salario mensual de los empleados que cobren mas que Jennifer ordenado por salario descendiente | ||
+--------------------+-------------------+ | +--------------------+-------------------+ | ||
| Nombre i apellido | Salario Mensual | | | Nombre i apellido | Salario Mensual | | ||
+--------------------+-------------------+ | +--------------------+-------------------+ | ||
− | + | <pre> | |
− | + | SELECT e.first_name||' '||e.last_name "Nombre i apellido"s, e.salary"Salario Mensual" | |
− | + | FROM employees e | |
− | + | WHERE e.salary >ANY (SELECT e.salary | |
− | |||
FROM employees e | FROM employees e | ||
WHERE UPPER(e.first_name)='JENNIFER'); | WHERE UPPER(e.first_name)='JENNIFER'); | ||
− | + | </pre> | |
− | + | 28) Para cada departamento Muestra el nombre del empleado/s que cobran menos. | |
+------------------------+-------------------+ | +------------------------+-------------------+ | ||
− | | Nombre | + | | Nombre departamento | Nombre empleado | |
+------------------------+-------------------+ | +------------------------+-------------------+ | ||
− | + | <pre> | |
− | + | SELECT d.department_name "Nombre departamento", e.first_name ||' '|| e.last_name "Nombre empleado" | |
− | + | FROM employees e JOIN departments d USING(department_id) | |
− | + | WHERE (department_id,e.salary) IN (SELECT e.department_id, min(e.salary) | |
− | |||
FROM employees e | FROM employees e | ||
− | GROUP BY e. | + | GROUP BY e.department_id); |
+ | </pre> | ||
− | + | 29) Para cada región muestra cuantos países hay. Ordena por numero de países ascendentemente. | |
− | |||
− | |||
+-----------------+-------------------+ | +-----------------+-------------------+ | ||
| Nombre Región | Numero de paises | | | Nombre Región | Numero de paises | | ||
+-----------------+-------------------+ | +-----------------+-------------------+ | ||
+ | <pre> | ||
+ | SELECT r.region_name "Nombre Region", count(*)"Numero de paises" | ||
+ | FROM regions r NATURAL JOIN countries c | ||
+ | GROUP BY r.region_name | ||
+ | ORDER BY 2 ASC; | ||
+ | </pre> | ||
− | + | 30) Muestra el nombre de los departamentos, nombre de su jefe i salario mensual, que se encuentran fuera de United States Of America. | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
+--------------+-------+-----------------+ | +--------------+-------+-----------------+ | ||
| Nombre Dep | Jefe | Sueldo Mensual | | | Nombre Dep | Jefe | Sueldo Mensual | | ||
+------------- +-------+-----------------+ | +------------- +-------+-----------------+ | ||
+ | <pre> | ||
+ | SELECT d.department_name "Nombre Dep", e.first_name "Jefe", e.salary "Sueldo Mensual" | ||
+ | FROM countries c NATURAL JOIN locations l NATURAL JOIN departments d JOIN employees e | ||
+ | ON (d.manager_id = e.employee_id) | ||
+ | WHERE c.country_name <> 'United States of America'; | ||
+ | </pre> | ||
− | + | 31) Mostrar el nombre de los países que empiezan o termina en una “a" junto con el nombre de la region a la que pertencen. | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
+-------------+--------+ | +-------------+--------+ | ||
| Nombre pais | Region | | | Nombre pais | Region | | ||
+-------------+--------+ | +-------------+--------+ | ||
+ | <pre> | ||
+ | SELECT c.country_name "Nombre país", r.region_name "Region" | ||
+ | FROM countries c NATURAL JOIN regions r | ||
+ | WHERE UPPER(c.country_name) LIKE 'A%' | ||
+ | OR UPPER(c.country_name) LIKE '%A'; | ||
+ | </pre> | ||
− | + | 32) Muestra el nombre de cada empleado en mayúsculas junto con el de su respectivo jefe. | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
+-----------------+-------------+ | +-----------------+-------------+ | ||
| Nombre empleado | Nombre jefe | | | Nombre empleado | Nombre jefe | | ||
+-----------------+-------------+ | +-----------------+-------------+ | ||
+ | <pre> | ||
+ | SELECT UPPER(e.first_name) "Nombre empleado", UPPER(j.first_name) "Nombre jefe" | ||
+ | FROM employees e JOIN employees j | ||
+ | on (e.manager_id=j.employee_id); | ||
+ | </pre> | ||
− | + | 33) Para cada jefe muestra cuantos empleados tiene a su cargo. | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
+-----------------+------------------+ | +-----------------+------------------+ | ||
| Nombre jefe | Numero empleados | | | Nombre jefe | Numero empleados | | ||
+-----------------+------------------+ | +-----------------+------------------+ | ||
+ | <pre> | ||
+ | SELECT j.first_name "Numero del jefe", COUNT(*)"Numero empleados" | ||
+ | FROM employees e JOIN employees j | ||
+ | on (e.manager_id=j.employee_id) | ||
+ | GROUP BY j.first_name; | ||
+ | </pre> | ||
− | + | 34) Cantidad de empleados que han ingresado en la empresa en cada año. | |
+-------+------------------+ | +-------+------------------+ | ||
| Año | Numero empleados | | | Año | Numero empleados | | ||
+-------+------------------+ | +-------+------------------+ | ||
+ | <pre> | ||
+ | SELECT TO_CHAR(e.hire_date,'YYYY') "Año", COUNT(*) | ||
+ | FROM employees e | ||
+ | GROUP BY TO_CHAR(e.hire_date,'YYYY'); | ||
+ | </pre> | ||
− | + | 35) Para cada empleado y cada puesto ocupado los meses que ha trabajado en dicho puesto. | |
+--------------+---------+------------------+ | +--------------+---------+------------------+ | ||
| Nombre emp | Puesto | Meses trabajados | | | Nombre emp | Puesto | Meses trabajados | | ||
+--------------+---------+------------------+ | +--------------+---------+------------------+ | ||
+ | <pre> | ||
+ | SELECT e.first_name "Nombre empleado",j.job_title "puesto", | ||
+ | ROUND(MONTHS_BETWEEN(jh.end_date,jh.start_date)) "Meses trabajados" | ||
+ | FROM employees e NATURAL JOIN jobs j JOIN job_history jh USING(job_id); | ||
+ | </pre> | ||
− | + | 36) El nombre de los jefes de cada departamento y su telefono. | |
+------------------------+------------------+---------------+ | +------------------------+------------------+---------------+ | ||
| Nombre departamento | Nombre jefe | Telefono jefe | | | Nombre departamento | Nombre jefe | Telefono jefe | | ||
+------------------------+------------------+---------------+ | +------------------------+------------------+---------------+ | ||
+ | <pre> | ||
+ | SELECT d.department_name "Nombre departamento", e.first_name "Nombre jefe", e.phone_number "telefono jefe" | ||
+ | FROM employees e, departments d | ||
+ | WHERE d.manager_id=e.employee_id; | ||
+ | </pre> | ||
− | + | 37) El costo de cada departamento en el ultimo año (suma de salario *12 de todos los empleados mas comisiones) | |
+------------------------+-----------------+ | +------------------------+-----------------+ | ||
− | | Nombre departamento | Coste año YYYY | | + | | Nombre departamento | Coste año YYYY | |
+-----------------------+------------------+ | +-----------------------+------------------+ | ||
+ | <pre> | ||
+ | SELECT d.department_name "Nombre departamento", SUM((e.salary*12)+NVL(e.comm))"Coste año 2015" | ||
+ | FROM departments d, employees e | ||
+ | WHERE d.department_id=e.department_id | ||
+ | GROUP BY d.department_name; | ||
+ | </pre> | ||
− | + | 38) Para cada departamento el promedio de sueldo, el salario maximo i el mínimo pero sólo mostrar los departamentos con promedio superior a la media de todos los departamentos. | |
− | |||
+------------------------+-----------------+-----------------+ | +------------------------+-----------------+-----------------+ | ||
| Nombre departamento | Sueldo medio | Salario maximo | | | Nombre departamento | Sueldo medio | Salario maximo | | ||
+------------------------+-----------------+-----------------+ | +------------------------+-----------------+-----------------+ | ||
+ | <pre> | ||
+ | SELECT d.department_name "Nombre departamento", ROUND(AVG(e.salary)) "Suedo medio", MAX(e.salary) "Salario máximo" | ||
+ | FROM departments d, employees e | ||
+ | WHERE d.department_id=e.department_id | ||
+ | GROUP BY d.department_name; | ||
+ | </pre> | ||
+ | --> |
Revisió de 19:11, 4 nov 2020
Solucions Repàs Consultes BBDD HR
1) Muestra los departamentos (departament_id) en los que sus empleados tienen un salario superior a todos los empleados de otro departamento.
SELECT department_id FROM employees WHERE department_id IS NOT NULL GROUP BY department_id HAVING min(salary) > ANY (SELECT max(salary) FROM employees GROUP BY department_id);
2) Igual que 1, pero mostrando también el nombre del departamento.
SELECT department_id, d.department_name FROM employees e JOIN departments d USING (department_id) WHERE department_id IS NOT NULL GROUP BY department_id, d.department_name HAVING min(salary) > ANY (SELECT max(salary) FROM employees GROUP BY department_id);
3) Igual que 1 pero mostrando los nombres de los empleados.
SELECT first_name, last_name, department_id FROM employees WHERE department_ID in (SELECT department_id FROM employees WHERE department_id IS NOT NULL GROUP BY department_id HAVING min(salary) > ANY (SELECT max(salary) FROM employees GROUP BY department_id));
4)Muestra id, last_name, salary i la media de salarios del departamento de su departamento para todos aquellos empleados que ganen más que la media de su departamento.
SELECT employee_id, last_name, salary, average.avgsalary FROM employees NATURAL JOIN (SELECT department_id, trunc(AVG(salary)) avgsalary FROM employees GROUP BY department_id) average WHERE salary > average.avgsalary;
5) Muestra id, first_name, last_name y hire_date de los 10 empleados más antiguos de la empresa.
SELECT rownum, first_name, last_name, hire_date FROM (SELECT first_name, last_name, hire_date FROM employees ORDER BY hire_date) WHERE rownum <=10;
6) Muestra id, first_name, last_name, nombre del departamento y salario de los 5 empleados mejor pagagados de la empresa.
SELECT rownum, first_name, last_name, salary, department_name FROM (SELECT first_name, last_name, salary, department_id FROM employees ORDER BY salary DESC) JOIN departments USING(department_id) WHERE rownum <=5;
12) Muestra el id, first_name, department_id, i salari del empleat(s) que guanyen més de cada departament.
SELECT employee_id, first_name, department_id, salary FROM employees NATURAL JOIN (SELECT department_id, MAX(salary) maxsal FROM employees GROUP BY department_id) MAXIMS WHERE salary = MAXIMS.maxsal;
SELECT employee_id, first_name, department_id, salary FROM employees e WHERE salary = (SELECT MAX(salary) FROM employees d WHERE d.department_id= e.department_id);
SELECT employee_id, first_name, department_id, salary FROM employees WHERE (salary, department_id) IN (SELECT MAX(salary), department_id FROM employees GROUP BY department_id);