SQL ("Structured Query Language") is an ANSI Standard computer language commonly used to access data stored in databases. With SQL you can:
Each RDBMS (DB2, MySQL, Oracle, SQL Server) follows the ANSI Standard to a large degree and then add value adding features. This tutorial will focus on the ANSI Standard and avoid vendor specific features.
SQL statements are represented as text.
SQL statements have keywords that must be spelled following rules. The keywords can be upper or lower case - SQL is not case sensitive. By convention and to improve readability, this tutorial spells SQL keywords in upper case.
SQL statements are independent of text lines. A single SQL statement can be placed on one text line or on multiple. In addition, multiple SQL statements can be combined on a single text line. By convention and to improve readability, this tutorial does not put more than one SQL statement on a single text line. Further, SQL statements are often broken into multiple lines.
A SQL statements may be terminated by a semi-colon or the word 'GO'. This tutorial leaves these terminators out. Please supply as needed.