SQL REFERENCE - Concepts of Database Management - page 356

The following query displays the customer number, last name, and first name of all customers that are
represented by sales rep 65 or that have orders or both:

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SELECT CustomerNum, CustomerName
FROM Customer
WHERE RepNum ¼' 35 '
UNION
SELECT Customer.CustomerNum, CustomerName
FROM Customer, Orders
WHERE Customer.CustomerNum=Orders.CustomerNum
;

UPDATE

Use the UPDATE command to change the contents of one or more rows in a table. Figure B-15 describes the
UPDATE command.

Clause Description Required?

UPDATE table name Indicates the name of the table whose contents

will be changed.

Yes

SET column = expression Indicates the column to be changed, along with

an expression that provides the new value.

Yes

WHERE condition Indicates a condition. The change will occur

only on those rows for which the condition is true.

No (If you omit the WHERE
clause, all rows will be updated.)

FIGURE B-15 UPDATE command

The following UPDATE command changes to 1445 Rivard the street address on the row in the Customer
table on which the customer number is 524:

UPDATE Customer
SET Street ¼' 1445 Rivard '
WHERE CustomerNum ¼' 524 '
;