Standard SQL is simple and straightforward. In fact, once you get the hang of it, you'll probably agree with most developers that it is the easiest language to learn and implement. The bulk of the language is composed of keywords, and learning how to arrange those keywords in the proper order is all you really have to master. The following is a list of a few grammar terms you'll see throughout this chapter:
Keyword An individual word with a predefined meaning or purpose
Clause A keyword complete with arguments
Statement A complete request that the RDBMS can interpret
A SQL statement can be as simple as one keyword and an argument, but most have a little more to them than that. A basic statement generally takes the form of the following:
action argument FROM datasource WHERE condition
In this statement, action specifies the type of task or request being sent to the database, argument usually identifies the specific columns of data involved, datasource is a table or query that contains the data, and condition is a criteria expression that limits the data acted upon in the request.
SQL can do far more than just retrieve and modify data. SQL can create and delete tables, define indexes, define relationships, and so on. Most of these tasks are more administrative and aren't needed in the average data request from a website. In this chapter, we'll provide a more in-depth review of the standard SQL statements and syntax that you'll need to retrieve and modify data.