This document contains several SQL queries: 1) A query that selects employee last names and calculates the months between hire date and current date. 2) A query that selects employee details including name, salary, years worked, and proposed salary increase. 3) Two UNIONed queries that count employees hired in 2003 and 2005 by job ID. 4) A query that selects employee details for those hired the same number of years as employee 'Lee'. 5) A query that selects the last hired employee's last name. 6) A query that counts employees grouped by country name using data from four tables.

1. REGIONS
LOCATIONS
JOB_HISTORY
COUNTRIES
EMPLOYEES
DEPARTMENTS
JOBS
practica
select last_name as "LAST_NAME", ROUND(MONTHS_BETWEEN(SYSDATE, HIRE_DATE)) AS
TIEMPO
from EMPLOYEES
ORDER BY TIEMPO desc
SELECT last_name ||' GANA s/'||SALARY||' ESTA TRABAJANDO '||
ROUND((MONTHS_BETWEEN(SYSDATE, HIRE_DATE)/12)) ||'AÑOS PERO QUIERE GANAR S/'||
(SALARY+(SALARY*10*ROUND(MONTHS_BETWEEN(SYSDATE, HIRE_DATE)/12))/100)
AS "Employee Details"
FROM employees
WHERE ROUND(MONTHS_BETWEEN(SYSDATE, HIRE_DATE)/12)>5
SELECT JOB_ID,COUNT (*), 2003 as lista
FROM employees
WHERE hire_date >TO_DATE('01-Jan-2003','DD-Mon-RR')AND hire_date<TO_DATE('01-
DEC-2003','DD-Mon-RR')
GROUP BY JOB_ID
UNION ALL
SELECT JOB_ID, COUNT (*), 2005 as lista
FROM employees
WHERE hire_date >TO_DATE('01-Jan-2005','DD-Mon-RR')AND hire_date<TO_DATE('01-
DEC-2005','DD-Mon-RR')
GROUP BY JOB_ID
___
SELECT FIRST_NAME,last_name, DEPARTMENT_ID, JOB_ID
FROM employees
WHERE ROUND(MONTHS_BETWEEN(SYSDATE, HIRE_DATE)/12)=(SELECT
ROUND(MONTHS_BETWEEN(SYSDATE, HIRE_DATE)/12) FROM employees WHERE
last_name='Lee') ORDER BY DEPARTMENT_ID ASC
;
_____
select last_name
from employees
where HIRE_DATE =(select max (HIRE_DATE)
from employees
)
select D.COUNTRY_NAME, COUNT (*)
from employees a,DEPARTMENTS b, LOCATIONS c, COUNTRIES d
where a.DEPARTMENT_ID=b.DEPARTMENT_ID and b.LOCATION_ID=c.LOCATION_ID AND
C.COUNTRY_ID=D.COUNTRY_ID
GROUP BY D.COUNTRY_NAME;