Chapter 1. Introductory Transact-SQL

The single biggest challenge to learning SQL programming is unlearning procedural programming.

—Joe Celko

SQL is the lingua franca of the database world. Most modern DBMSs use some type of SQL dialect as their primary query language, including SQL Server. You can use SQL to create or destroy objects on the database server such as tables and to do things with those objects, such as put data into them or query them for that data. No single vendor owns SQL, and each is free to tailor the language to better satisfy its own customer base. Despite this latitude, there is a multilateral agreement against which each implementation is measured. It's commonly referred to as the ANSI/ISO SQL standard and is governed by the National Committee on Information Technology Standards (NCITS H2). This standard is actually several standards—each named after the year in which it was adopted. Each standard builds on the ones before it, introducing new features, refining language syntax, and so on. The 1992 version of the standard—commonly referred to as SQL-92—is probably the most popular of these and is definitely the most widely adopted by DBMS vendors. As with other languages, vendor implementations of SQL are rated according to their level of compliance with the ANSI/ISO standard. Most vendors are compliant with at least the entry-level SQL-92 specification, though some go further.