Share this page:

sql tutorial

SQL: CREATE TABLE Statement

This SQL tutorial explains how to use the SQL CREATE TABLE statement with syntax, examples, and practice exercises.

Description

The SQL CREATE TABLE statement allows you to create and define a table.

Syntax

The syntax for the SQL CREATE TABLE statement is:

CREATE TABLE table_name
( 
  column1 datatype null/not null,
  column2 datatype null/not null,
  ...
);

Parameters or Arguments

table_name is the name of the table that you wish to create.

column1, column2 are the columns that you wish to create in the table. Each column must have a datatype. The column should either be defined as "null" or "not null" and if this value is left blank, the database assumes "null" as the default.

Example

Let's look at a SQL CREATE TABLE example.

CREATE TABLE suppliers
( supplier_id number(10) not null,
  supplier_name varchar2(50) not null,
  contact_name varchar2(50)
);

This SQL CREATE TABLE example creates a table called suppliers which has 3 columns.

  • The first column is called supplier_id which is created as a number datatype (maximum 10 digits in length) and can not contain null values.
  • The second column is called supplier_name which is a varchar2 datatype (50 maximum characters in length) and also can not contain null values.
  • The third column is called contact_name which is a varchar2 datatype but can contain null values.

Now the only problem with this SQL CREATE TABLE statement is that you have not defined a primary key for the table. We could modify this SQL CREATE TABLE statement and define the supplier_id as the primary key as follows:

CREATE TABLE suppliers
( supplier_id number(10) not null,
  supplier_name varchar2(50) not null,
  contact_name varchar2(50),
  CONSTRAINT suppliers_pk PRIMARY KEY (supplier_id)
);

Learn about primary keys.

Learn about foreign keys.

Practice Exercise #1:

Create a SQL table called customers that stores customer ID, name, and address information.

Solution for Practice Exercise #1:

The SQL CREATE TABLE statement for the customers table is:

CREATE TABLE customers
( customer_id number(10) not null,
  customer_name varchar2(50) not null,
  address varchar2(50),
  city varchar2(50),
  state varchar2(25),
  zip_code varchar2(10)
);

Practice Exercise #2:

Create a SQL table called customers that stores customer ID, name, and address information.

But this time, the customer ID should be the primary key for the table.

Solution for Practice Exercise #2:

The SQL CREATE TABLE statement for the customers table is:

CREATE TABLE customers
( customer_id number(10) not null,
  customer_name varchar2(50) not null,
  address varchar2(50),
  city varchar2(50),
  state varchar2(25),
  zip_code varchar2(10),
  CONSTRAINT customers_pk PRIMARY KEY (customer_id)
);

Practice Exercise #3:

Based on the departments table below, create a SQL table called employees that stores employee number, employee name, department, and salary information. The primary key for the employees table should be the employee number. Create a foreign key on the employees table that references the departments table based on the department_id field.

CREATE TABLE departments
( department_id number(10) not null,
  department_name varchar2(50) not null,
  CONSTRAINT departments_pk PRIMARY KEY (department_id)
);

Solution for Practice Exercise #3:

The SQL CREATE TABLE statement for the employees table is:

CREATE TABLE employees
( employee_number number(10) not null,
  employee_name varchar2(50) not null,
  department_id number(10),
  salary number(6),
  CONSTRAINT employees_pk PRIMARY KEY (employee_number),
  CONSTRAINT fk_departments
    FOREIGN KEY (department_id)
    REFERENCES departments(department_id)
);