GROUP BY==========
SELECT EMPLOYEE_CITY,
       AVG(SALARY) AS AVG_SAL
FROM EMPLOYEE 
GROUP BY EMPLOYEE_CITY;
 
GROUP BY MULTIPLE==========
SELECT CUST_CITY, TYPE, 
       SUM(BALANCE) AS TOTAL_BALANCE
FROM CUSTOMER
NATURAL JOIN DEPOSITOR
NATURAL JOIN ACCOUNT
GROUP BY CUST_CITY, TYPE;
 
HAVING========
SELECT employee_city, AVG(salary) AS avg_salary
FROM employee
GROUP BY employee_city
HAVING AVG(salary) > 50000;
 
HAVING MULTIPLE========
SELECT CUST_CITY, TYPE, AVG(BALANCE) AS AVG_BAL
FROM CUSTOMER
NATURAL JOIN DEPOSITOR
NATURAL JOIN ACCOUNT
GROUP BY CUST_CITY, TYPE
HAVING AVG(BALANCE) > 5000;
 
WHERE GROUP BY HAVING ORDER BY together=========
SELECT employee_city, AVG(salary) AS avg_salary
FROM employee
WHERE employee_startdate > '01-JAN-80'
GROUP BY employee_city
HAVING AVG(salary) > 1000
ORDER BY AVG(salary) DESC;
 
Nested group quick========
SELECT MAX(AVG(salary))
FROM employee
GROUP BY employee_city;
 
SELECT INTO condition=======
DECLARE
 v_salary employee.salary%TYPE;
BEGIN
 SELECT salary INTO v_salary
 FROM employee
 WHERE employee_id = 'E001';
 IF v_salary > 50000 THEN
 DBMS_OUTPUT.PUT_LINE('High Salary');
 ELSIF v_salary >= 30000 THEN
 DBMS_OUTPUT.PUT_LINE('Medium Salary');
 ELSE
 DBMS_OUTPUT.PUT_LINE('Low Salary');
 END IF;
END;
 
CURSOR===============
DECLARE
 CURSOR emp_cursor IS
 SELECT employee_name, employee_id
 FROM employee
 WHERE employee_id LIKE 'E%';
 emp_val emp_cursor%ROWTYPE;
BEGIN
 OPEN emp_cursor;
 LOOP
 FETCH emp_cursor INTO emp_val;
 EXIT WHEN emp_cursor%NOTFOUND;
 DBMS_OUTPUT.PUT_LINE(emp_val.employee_name);
 END LOOP;
 CLOSE emp_cursor;
END;
 

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