Slide 7.9: SQL select distinct statement

SQL Select Distinct Statement

The DISTINCT keyword can be used to return only distinct (different) values. In a table, some of the columns may contain duplicate values.

This is not a problem, however, sometimes you will want to list only the different (distinct) values in a table.

 SELECT  DISTINCT column_name(s)
   FROM  table_name

In the example below, the company W3Schools is listed twice in the result-set if the keyword DISTINCT is not used. To select only different values from the column named Company, we use a select distinct statement.

 CREATE TABLE  Orders (
   Company      VARCHAR(32),
   OrderNumber  NUMBER(4)  NOT NULL);

 Table created.

 INSERT INTO  Orders  VALUES ('Sega', 3412);
 INSERT INTO  Orders  VALUES ('W3Schools', 2312);
 INSERT INTO  Orders  VALUES ('Trio', 4678);
 INSERT INTO  Orders  VALUES ('W3Schools', 6798);
 SELECT  Company  FROM  Orders;

 COMPANY
 --------------------------------
 Sega
 W3Schools
 Trio
 W3Schools

 SELECT DISTINCT  Company  FROM  Orders;

 COMPANY
 --------------------------------
 Sega
 Trio
 W3Schools

Demonstration
The following is an SQL test area from W3Schools, which uses the well-known Northwind sample database and the tables are for read only.

For security reasons, the following demonstration may only work in Chrome.

Result:

Click “Run SQL” to execute the SQL statement above.

W3Schools has created an SQL database in your browser.

The menu to the right displays the database, and will reflect any changes.

Feel free to experiment with any SQL statement.

You can restore the database at any time.

The Database includes:

The Database includes:

Tablenames	Records
Customers	91
Categories	8
Employees	10
OrderDetails	518
Orders	196
Products	77
Shippers	3
Suppliers	29