2 The Essential PROC SQL Handbook
A little history
SQL is a powerful, flexible, fourth-generation sublanguage that enables complex
processing through a few simple statements. You need only to indicate the desired
outcome rather than outline each of the steps necessary to reach that outcome because
SQL is a nonprocedural language. SQL statements allow for the complete creation,
maintenance, and reporting of relational database systems using English-like statements.
In the mid-1970s the Structured Query Language (SQL) was developed by IBM
researchers in San Jose, California, to support a new relational database model. In June
1970, Dr. E. F. Codd, a researcher with IBM, published his mathematical theory of data
management in a paper entitled "A Relational Model of Data for Large Shared Data
Banks." His ideas resulted in the definition of a new form of data storage structure, a
table consisting of rows and columns. The relational database model was thus born from
tables and the relationships between tables.
SQL was designed to enable access to data stored in a relational database. It allows you
to create, alter, and delete tables as well as modify or delete existing records or add new
records to tables.
By the late 1980s and early 1990s, each database vendor had its own version of SQL. In
an effort to minimize the inconsistencies and provide portability of SQL statements, the
American National Standards Institute (ANSI) developed a set of international standards
to be applied to the language. Several standards have been published by ANSI since
1986, including SQL-89, SQL-92, SQL-99 and SQL-2003.
Each successive SQL language release extends functionality. However, the foundations
of the SQL language have remained mostly unchanged. Vendors that are compliant with
the ANSI SQL-92 standard, for example, are also compliant with the SQL-99 core
function standards.
The power and ease-of-use of SQL has resulted in its use in hundreds of database
products today. Companies such as Oracle, Microsoft, Sybase, and IBM depend heavily
on SQL in their database products regardless of operating system. As a result, anyone
working with databases today must be proficient in SQL. The ANSI standards have
resulted in a set of more or less common statements with agreed upon functionality from
each vendor. However, many different ideas and syntactical differences are found in
each flavor of SQL.
PROC SQL underwent major change in SAS Version 8, resulting in a more versatile
procedure that is also more closely in line with the ANSI SQL-92 standard. The new
version extends the functionality of the SQL language with elements from Base SAS.