2_Queries_presentation_l2_v1

Queries

Select queries

A select query is the most common type of query.
It retrieves data from one or more tables and displays the results in a datasheet where you can update the records (with some restrictions).
You can also use a select query to group records and calculate sums, counts, averages, and other types of totals.

Computer store example

Let’s consider the following database as an example. (More precisely, this is a database schema, or database layout, independent of the actual data it contains.)
It consists of 4 related tables, containing fields as indicated.

Let’s suppose the Customers table contains the following data:

Let’s create a select query that shows only those records for customers in Miami.
We double-click “Create query in Design view” in the Database Window.
“Select Query” will be the default query type when we start in Design View, but we can go to the Query Type button to set it as desired.

We then click the Show Table button to select the tables the query is to use. In this case we use only the Customers table.
The query design window has an upper pane and a lower pane.
The upper pane shows the tables we’ve selected and their relationships, while the lower pane shows the design grid.