The Update Query is an Access SQL command used to modify existing data in your relational database tables.

Query Syntax

Update TableName Set ColumnName=somevalue Where somecriteria;
Note: The ending semicolon is a required component of all SQL statements.

Here is shown a real-life example of the query in action:

Update M_Employees Set Emp_Name="Cheryl Crow",  Marital_Status="Available" Where Emp_Name="Cheryl Armstrong";

If you leave the Where Clause out of the query then all of the records will get updated.

Instructions for creating an update query (paraphrased from Microsoft Access Instructions):

Create a query with the table(s) containing the data you would like to update, in our example it is the Employee table.  See the image below to view the query design grid screen.

• In the Database window, click Queries and then click New on the Database window toolbar.
   

• See a real-life update query example: Change Table Data

  In the New Query dialog box, click Design View, and then click OK.
  3. In the Show Table dialog box, click the tab that lists the tables or queries whose data you want to work with.
   

• Double-click the employee table to add to the query, and then click Close.
   

• Add fields (salary) to the Field row in the design grid, and if you want, specify criteria and a sort order.
   

• To view the query's results, click View on the toolbar.
   

• In query Design view, click the arrow next to Query Type on the toolbar, and then click Update Query.
   

• Drag from the Salary field to the query design grid the fields you want to update or for which you want to specify criteria.
   

• In the Criteria cell, specify the criteria if necessary.
   

• In the Update To cell for the fields you want to update, type the expression ([salary] + 100.00) or value you want to use to change the fields, as shown in the following illustration.
   

• To see a list of the records that will be updated, click View on the toolbar. This list won't show the new values. To return to query Design view, click View on the toolbar again. Make any changes you want in Design view.
   

• Click Run on the toolbar to update the records.