SQL UPDATE Statement

How do I update values in a database?

The UPDATE statement updates data values in a database.
UPDATE can update one or more records in a table.
Use the WHERE clause to UPDATE only specific records.

The SQL UPDATE syntax

The general syntax is

UPDATE table-name 
   SET column-name1 = value1, 
       column-name2 = value2, ...

To limit the number of records to UPDATE append a WHERE clause:

UPDATE table-name 
   SET column-name1 = value1, 
       column-name2 = value2, ...
 WHERE condition

PRODUCT
Id
ProductName
SupplierId
UnitPrice
Package
IsDiscontinued

SQL UPDATE Examples

Problem: Discontinue all products in the database

UPDATE Product
   SET IsDiscontinued = 1

Note: the value 1 denotes true.

Result: 77 records updated.

PRODUCT
Id
ProductName
SupplierId
UnitPrice
Package
IsDiscontinued

Problem: Discontinue products over $50.

UPDATE Product
   SET IsDiscontinued = 1
 WHERE UnitPrice > 50

Note: the value 1 denotes true.

Result: 7 records updated.

PRODUCT
Id
ProductName
SupplierId
UnitPrice
Package
IsDiscontinued

Problem: Discontinue product with Id = 46.

UPDATE Product
   SET IsDiscontinued = 1
 WHERE Id = 46

This is a more common scenario in which a single record is updated.
Note: the value 1 denotes true.

Result: 1 record updated.

SUPPLIER
Id
CompanyName
ContactName
City
Country
Phone
Fax

Problem: Supplier Norske Meierier (Id = 15) has moved:
update their city, phone and fax.

UPDATE Supplier
   SET City = 'Oslo', 
       Phone = '(0)1-953530', 
       Fax = '(0)1-953555'
 WHERE Id = 15

This is a common scenario in which a single record is updated.

Result: 1 record updated.