SQL Update

The SQL UPDATE Statement

The UPDATE statement is used to update or modify one or more records in a table.

UPDATE Syntax

<p><code class="sqlHigh">
 UPDATE <em>table_name</em><br/>
 SET <em>column1 </em>=<em> value1</em>,<em> column2 </em>=<em> value2</em>, ...<br/>
 WHERE <em>condition</em>;</code></p>

Note: Be careful when updating records in a table! Notice the WHERE clause in the UPDATE statement. The WHERE clause specifies which record(s) that should be updated. If you omit the WHERE clause, all records in the table will be updated!

Demo Database

Below is a selection from the Customers table used in the examples:

UPDATE Table

The following SQL updates the record with CustomerID = 1, with a new contact person AND a new city.

Example

UPDATE Customers

SET ContactName = 'Alfred Schmidt', City= 'Frankfurt'

WHERE CustomerID = 1;

The selection from the "Customers" table will now look like this:

UPDATE Multiple Records

The WHERE clause determines which records that will be updated.

The following SQL will update the ContactName to "Juan" for ALL records where country is "Mexico":

Example

UPDATE Customers

SET ContactName='Juan'

WHERE Country='Mexico';

The selection from the "Customers" table will now look like this:

Update Warning!

Note: Be careful when updating records. If you omit the WHERE clause, ALL records will be updated!

The following SQL will update the ContactName to "Juan" for ALL records:

Example

UPDATE Customers

SET ContactName='Juan';

The selection from the "Customers" table will now look like this: