SQL Example

CREATE TABLE STUDENTS ( 
    ID INTEGER PRIMARY KEY, 
    FIRST_NAME VARCHAR(50) NOT NULL, 
    LAST_NAME VARCHAR(50) NOT NULL, 
    ADDRESS VARCHAR(100) 
);

CREATE TABLE ORDERS
(
    Id INTEGER PRIMARY KEY,
    StudentId INTEGER,
    test ARCHAR(100),
    FOREIGN KEY (StudentId)  REFERENCES STUDENTS (id)
);

INSERT INTO students VALUES (1, 'Dima', 'Lyapun', NULL);
INSERT INTO students VALUES (2, 'Ivan', 'Ivanon', 'My address');
INSERT INTO students VALUES (3, 'Alex', 'Cooper', 'Odessa, Ua');
INSERT INTO students VALUES (4, 'Alex', 'Second', 'Odessa, Ua');

UPDATE students SET first_name = 'Dmytro', last_name = 'Lyao' WHERE first_name = 'Dima'; 

INSERT INTO ORDERS VALUES (1, 2, 'Simple Order data');

SELECT first_name, last_name from STUDENTS WHERE id = 1;
SELECT id, last_name from STUDENTS WHERE id > 2 ;
SELECT first_name from STUDENTS GROUP BY first_name;

SELECT last_name from STUDENTS WHERE id < 3 ORDER BY last_name;

SELECT * FROM ORDERS INNER JOIN STUDENTS ON orders.StudentId = Students.id;

SELECT id, first_name, last_name from STUDENTS WHERE id = 2 AND first_name = 'Ivan';
SELECT first_name, last_name from STUDENTS WHERE id IN (2,3);