RELATIONAL DATA RETRIEVAL: SQL - Fundamentals of Database Management Systems - page 75

As another example:

''List the customer numbers and headquarters cities of the customers that have
a customer number of at least 1700.''

SELECT CUSTNUM, HQCITY
FROM CUSTOMER
WHERE CUSTNUM > =1700;

results in:

CUSTNUM HQCITY

1700 Washington

1826 New York

2198 New York

2267 New York

ANDs and ORs Frequently, there is a need to specify more than one limiting
condition on a table's rows in a query. Sometimes, for a row to be included in
the result it must satisfy more than one condition. This requires the Boolean AND
operator. Sometimes a row can be included if it satisfies one of two or more
conditions. This requires the Boolean OR operator.

AND An example in which two conditions must be satisfied is:

''List the customer numbers, customer names, and headquarters cities of the
customers that are headquartered in New York and that have a customer number
higher than 1500.''

SELECT CUSTNUM, CUSTNAME, HQCITY
FROM CUSTOMER
WHERE HQCITY='New York'
AND CUSTNUM > 1500;

resulting in:

CUSTNUM CUSTNAME HQCITY

1826 City Hardware New York

2198 Western Hardware New York

2267 Central Stores New York

Notice that customer number 0121, which is headquartered in New York, was
not included in the results because it failed to satisfy the condition of having a
customer number greater than 1500. With the AND operator, it had to satisfy both
conditions to be included in the result.

OR

To look at the OR operator, let's change the last query to:
''List the customer numbers, customer names, and headquarters cities of the
customers that are headquartered in New York or that have a customer number
higher than 1500.''