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SQL UPDATE Statement

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The UPDATE statement is used to update records in a table.

The SQL UPDATE Statement

The UPDATE statement is used to update existing records in a table.

SQL UPDATE Syntax

UPDATE table_name
SET column1=value1,column2=value2,...
WHERE some_column=some_value;

Notice the WHERE clause in the SQL UPDATE statement!
The WHERE clause specifies which record or records that should be updated. If you omit the WHERE clause, all records will be updated!

Demo Database

In this tutorial we will use the well-known Northwind sample database.

Below is a selection from the "Customers" table:

CustomerID CustomerName ContactName Address City PostalCode Country
1

 Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitucion 2222 Mexico D.F. 05021 Mexico
3 Antonio Moreno Taqueria Antonio Moreno Mataderos 2312 Mexico D.F. 05023 Mexico
4

 Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbkop Christina Berglund Berguvsvagen 8 Lulea S-958 22 Sweden

SQL UPDATE Example

Assume we wish to update the customer "Alfreds Futterkiste" with a new contact person and city.

We use the following SQL statement:

Example

UPDATE Customers
SET ContactName='Alfred Schmidt', City='Hamburg'
WHERE CustomerName='Alfreds Futterkiste';
Try it Yourself »

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

CustomerID CustomerName ContactName Address City PostalCode Country
1

 Alfreds Futterkiste Alfred Schmidt Obere Str. 57 Hamburg 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitucion 2222 Mexico D.F. 05021 Mexico
3 Antonio Moreno Taqueria Antonio Moreno Mataderos 2312 Mexico D.F. 05023 Mexico
4

 Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbkop Christina Berglund Berguvsvagen 8 Lulea S-958 22 Sweden

Update Warning!

Be careful when updating records. If we had omitted the WHERE clause, in the example above, like this:

UPDATE Customers
SET ContactName='Alfred Schmidt', City='Hamburg';

The "Customers" table would have looked like this:

CustomerID CustomerName ContactName Address City PostalCode Country
1

 Alfreds Futterkiste Alfred Schmidt Obere Str. 57 Hamburg 12209 Germany
2 Ana Trujillo Emparedados y helados Alfred Schmidt Avda. de la Constitucion 2222 Hamburg 05021 Mexico
3 Antonio Moreno Taqueria Alfred Schmidt Mataderos 2312 Hamburg 05023 Mexico
4

 Around the Horn Alfred Schmidt 120 Hanover Sq. Hamburg WA1 1DP UK
5 Berglunds snabbkop Alfred Schmidt Berguvsvagen 8 Hamburg S-958 22 Sweden

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