The AND & OR Keywords

AND and OR join two or more conditions in a WHERE clause. The AND operator displays a row if ALL conditions listed are true. The OR operator displays a row if ANY of the conditions listed are true.

 LastName   FirstName   Address   City 
Hansen Ola Timoteivn 10 Sandnes
Svendson Tove Borgvn 23 Sandnes
Pettersen Kari Storgt 20 Stavanger

Use AND to display each person with the first name equal to Tove, and the last name equal to Svendson: 
 SELECT  *  FROM  Persons
   WHERE  FirstName = 'Tove'
     AND  LastName = 'Svendson'

 LastName   FirstName   Address   City 
Svendson Tove Borgvn 23 Sandnes

Use OR to display each person with the first name equal to Tove, or the last name equal to Svendson: 
 SELECT  *  FROM  Persons
   WHERE  FirstName = 'Tove'
     OR   LastName  = 'Svendson'

 LastName   FirstName   Address   City 
Svendson Tove Borgvn 23 Sandnes
Svendson Stephen Kaivn 18 Sandnes

You can also combine AND and OR (use parentheses to form complex expressions): 
 SELECT  *  FROM  Persons
   WHERE (FirstName = 'Tove'
     OR   FirstName = 'Stephen')
     AND  LastName  = 'Svendson'

 LastName   FirstName   Address   City 
Svendson Tove Borgvn 23 Sandnes
Svendson Stephen Kaivn 18 Sandnes


The following is an SQL test area from w3schools.com where the Customers table may be created by the following command: 
   SQL> create table  Customers (
     2    CustomerID   varchar(16),
     3    CompanyName  varchar(32),
     4    ContactName  varchar(32),
     5    Address      varchar(64),
     6    City         varchar(32),
     7    PostalCode   varchar(16),
     8    Country      varchar(32) );
 Note that the Customers table is for read only.