Creates an update query that changes values in fields in a specified table based on specified criteria.
Syntax
UPDATE table
SET newvalue
WHERE criteria;
The UPDATE statement has these parts:
|
Part |
Description |
|
table |
The name of the table containing the data you want to modify. |
|
newvalue |
An expression that determines the value to be inserted into a particular field in the updated records. |
|
criteria |
An expression that determines which records will be updated. Only records that satisfy the expression are updated. |
Remarks
UPDATE is especially useful when you want to change many records or when the records that you want to change are in multiple tables.
You can change several fields at the same time. The following example increases the Order Amount values by 10 percent and the Freight values by 3 percent for shippers in the United Kingdom:
UPDATE Orders
SET OrderAmount = OrderAmount * 1.1,
Freight = Freight * 1.03
WHERE ShipCountryRegion = 'UK';
Important:
-
UPDATE does not generate a result set. Also, after you update records using an update query, you cannot undo the operation. If you want to know which records were updated, first examine the results of a select query that uses the same criteria, and then run the update query.
-
Maintain backup copies of your data at all times. If you update the wrong records, you can retrieve them from your backup copies.
