MS Access for the Business Environment: Access Query Techniques: Using the TOP Keyword
January 5, 2004
About the Series ...
This article continues the series, MS Access for the Business Environment. The primary focus of this series is an examination of business uses for the MS Access relational database management system. The series is designed to provide guidance in the practical application of data and database concepts to meet specific needs in the business world. The majority of the procedures I demonstrate in this article and going forward will be undertaken with MS Access 2003, although most of the concepts that we explore in the series will apply to earlier versions of MS Access, as well.
For more information on the series, as well as the hardware / software requirements to prepare for the tutorials we will undertake, please see Tutorial 1: Create a Calculated Field with the Expression Builder.
Introduction to this Tutorial
In our last lesson, Access Query Techniques: Subqueries, Part I, we introduced subqueries within the context of MS Access, and practiced their creation and use in rendering a result dataset to meet illustrative business needs. As a part of our exploration of subqueries, we examined the syntax surrounding the use of a straightforward sample subquery; we then began an illustrative, hands-on example of the use of a subquery in a multi-step practice exercise. After evolving an initial query, we created a second query, within which we nested the first, to demonstrate the operation of a subquery in our practice exercise. Finally, we briefly discussed various aspects of the results datasets that we obtained in each step of the practice examples.
Before moving to our next article, Access Query Techniques: Subqueries, Part II, we will first consider a keyword whose use we will see again in the second half of our exploration of subqueries, as well as elsewhere. We will overview the TOP keyword, and get a feel for its operation in an undistracted scenario, before proceeding into the creation of a subquery that leverages the keyword to illustrate more sophistication in the use of subqueries than we saw in Part I.
The objective of this lesson is to introduce the TOP keyword as it is used in Microsoft Jet SQL, and to explore ways we can use it to meet illustrative business needs. To accomplish this, we will follow our approach in previous lessons, and perform the following activities surrounding our examination of the TOP keyword:
We will use the Northwind sample database that installs with MS Access for purposes of this lesson, in an attempt to make our discussion useful to virtually anyone who has access to the application.