Basics

Create table

--Create the main employee table
CREATE TABLE employee (
  id int PRIMARY KEY,
  name varchar(255),
  age int
);

--Create the employee age table
CREATE TABLE employee_age (
  id int PRIMARY KEY,
  age int
);

Insert

INSERT INTO employee
  VALUES (1, 'Ashish', 'Pune');
INSERT INTO employee
  VALUES (2, 'patel', 'Nagpur');
INSERT INTO employee
  VALUES (4, 'Ansu', 'Bikaner');

INSERT INTO employee_age
  VALUES (1, 23);
INSERT INTO employee_age
  VALUES (2, 27);
INSERT INTO employee_age
  VALUES (3, 21);

Select

SELECT * FROM employee;

id	name	city
1	Ashish	Pune
2	patel	Nagpur
4	Ansu	Bikaner

SELECT * FROM employee_age;

id	age
1	23
2	27
3	21