One of the core skills required by database professionals is the ability to manipulate and retrieve data held in a database using Structured Query Language (SQL, sometimes pronounced "sequel"). As we'll see, queries can be written to create tables, add records to tables, update existing table records, and retrieve records meeting certain criteria. This last function, retrieving data through SELECT queries, is arguably the most important because of its utility in answering the questions that led the database developer to create the database in the first place. SELECT queries are also the most fun type to learn about, so, in this first lesson, we will focus on using them to retrieve data from an existing database. Later, we'll see how new databases can be designed, implemented, populated and updated using other types of queries.
At the successful completion of this lesson, students should be able to:
- use the Query Builder GUI in MS-Access to create basic SQL SELECT queries;
- understand how settings made in the Query Builder translate to the various clauses in an SQL statement;
- use aggregation functions on grouped records to calculate counts, sums, and averages;
- construct a query based on another query (subquery).
Conversation and comments in this course will take place within the course discussion forums. If you have any questions now or at any point during this week, please feel free to post them to the Lesson 1 Discussion Forum.