SQL Basics

SQL ("Structured Query Language") is an ANSI Standard computer language commonly used to access data stored in databases. With SQL you can:

• Retrieve data from a database querying using the SQL SELECT Statement
• Control which data is accessed using the SQL WHERE Clause
• Insert rows into a database using the SQL INSERT Statement
• Update rows in a database using the SQL UPDATE Statement
• Delete rows from a database using the SQL UPDATE Statement

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.