Preface

This reference contains a complete description of the Structured Query Language (SQL) used to manage information in an Oracle database. Oracle SQL is a superset of the American National Standards Institute (ANSI) and the International Standards Organization (ISO) SQL99 standard.

This preface contains these topics:

Audience

The Oracle9i SQL Reference is intended for all users of Oracle SQL.

Organization

This reference is divided into the following parts:

Chapter 1, "Introduction to Oracle SQL"

This chapter discusses the history of SQL and describes the advantages of using it to access relational databases.

Chapter 2, "Basic Elements of Oracle SQL"

This chapter describes the basic building blocks of an Oracle database and of Oracle SQL.

Chapter 3, "Operators"

This chapter describes SQL operators.

Chapter 4, "Expressions"

This chapter describes SQL expressions.

Chapter 5, "Conditions"

This chapter describes SQL conditions.

Chapter 6, "Functions"

This chapter describes how to use SQL functions.

Chapter 7, "Common SQL DDL Clauses"

This chapter describes a number of DDL clauses that are frequently used in multiple top-level SQL statements.

Chapter 8, "SQL Queries and Subqueries"

This chapter describes the different types of SQL queries and lists the various types of SQL statements.

Chapter 9, "SQL Statements: ALTER CLUSTER to ALTER SEQUENCE"

Chapter 10, "SQL Statements: ALTER SESSION to ALTER SYSTEM"

Chapter 11, "SQL Statements: ALTER TABLE to ALTER TABLESPACE"

Chapter 12, "SQL Statements: ALTER TRIGGER to COMMIT"

Chapter 13, "SQL Statements: CREATE CLUSTER to CREATE JAVA"

Chapter 14, "SQL Statements: CREATE LIBRARY to CREATE SPFILE"

Chapter 15, "SQL Statements: CREATE SYNONYM to CREATE TRIGGER"

Chapter 16, "SQL Statements: CREATE TYPE to DROP ROLLBACK SEGMENT"

Chapter 17, "SQL Statements: DROP SEQUENCE to ROLLBACK"

Chapter 18, "SQL Statements: SAVEPOINT to UPDATE"

Chapters 9 through 18 list and describe all Oracle SQL statements in alphabetical order.

Appendix A, "How to Read Syntax Diagrams"

This appendix describes how to read the syntax diagrams in this reference.

Appendix B, "Oracle and Standard SQL"

This appendix describes Oracle compliance with ANSI and ISO standards.

Appendix C, "Oracle Reserved Words"

This appendix lists words that are reserved for internal use by Oracle.

Appendix D, "Examples"

This appendix provides extended examples that use multiple SQL statements and are therefore not appropriate for any single section of the reference.

Structural Changes in the SQL Reference in Oracle9i Release 2 (9.2)

The following frequently used DDL clauses have been separated into their own chapter, Chapter 7, "Common SQL DDL Clauses": allocate_extent_clause, constraints, deallocate_unused_clause, file_specification, logging_clause, parallel_clause, physical_attributes_clause, storage_clause.

In earlier releases, the autoextend_clause appeared in a number of SQL statements. It now is documented as part of the datafile_tempfile_spec form of file_specification, to clarify that this attribute relates to datafiles and tempfiles.

Structural Changes in the SQL Reference in Oracle9i Release 1 (9.0.1)

The chapter that formerly described expressions, conditions, and queries has been divided. Conditions and expressions are now two separate chapters, and queries are described in Chapter 8, "SQL Queries and Subqueries".

CAST, DECODE, and EXTRACT (datetime), which were formerly documented as forms of expression, are now documented as SQL built-in functions.

LIKE and the elements formerly called "comparison operators" and "logical operators" are now documented as SQL conditions.

The chapters containing all SQL statements (formerly Chapters 7 through 10) have been divided into ten chapters for printing purposes.

Conventions

This section describes the conventions used in the text and code examples of this documentation set. It describes:

Conventions in Text

We use various conventions in text to help you more quickly identify special terms. The following table describes those conventions and provides examples of their use.

Convention	Meaning	Example
Bold	Bold typeface indicates terms that are defined in the text or terms that appear in a glossary, or both.	When you specify this clause, you create an index-organized table.
Italics	Italic typeface indicates book titles or emphasis.	Oracle9i Database Concepts Ensure that the recovery catalog and target database do not reside on the same disk.
`UPPERCASE monospace (fixed-width) font`	Uppercase monospace typeface indicates elements supplied by the system. Such elements include parameters, privileges, datatypes, RMAN keywords, SQL keywords, SQL*Plus or utility commands, packages and methods, as well as system-supplied column names, database objects and structures, usernames, and roles.	You can specify this clause only for a `NUMBER` column. You can back up the database by using the `BACKUP` command. Query the `TABLE_NAME` column in the `USER_TABLES` data dictionary view. Use the `DBMS_STATS`.`GENERATE_STATS` procedure.
`lowercase monospace (fixed-width) font`	Lowercase monospace typeface indicates executables, filenames, directory names, and sample user-supplied elements. Such elements include computer and database names, net service names, and connect identifiers, as well as user-supplied database objects and structures, column names, packages and classes, usernames and roles, program units, and parameter values. Note: Some programmatic elements use a mixture of UPPERCASE and lowercase. Enter these elements as shown.	Enter `sqlplus` to open SQL*Plus. The password is specified in the `orapwd` file. Back up the datafiles and control files in the `/disk1/oracle/dbs` directory. The `department_id`, `department_name`, and `location_id` columns are in the `hr.departments` table. Set the `QUERY_REWRITE_ENABLED` initialization parameter to `true.` Connect as `oe` user. The `JRepUtil` class implements these methods.
`lowercase italic monospace (fixed-width) font`	Lowercase italic monospace font represents placeholders or variables.	You can specify the `parallel_clause`. Run `U``old_release``.SQL` where `old_release` refers to the release you installed prior to upgrading.

Conventions in Code Examples

Code examples illustrate SQL, PL/SQL, SQL*Plus, or other command-line statements. They are displayed in a monospace (fixed-width) font and separated from normal text as shown in this example:

SELECT username FROM dba_users WHERE username = 'MIGRATE';

The following table describes typographic conventions used in code examples and provides examples of their use.

Convention	Meaning	Example
[ ]	Brackets enclose one or more optional items. Do not enter the brackets.	`DECIMAL (``digits` `[ ,` `precision` `])`
{ }	Braces enclose two or more items, one of which is required. Do not enter the braces.	`{ENABLE \| DISABLE}`
\|	A vertical bar represents a choice of two or more options within brackets or braces. Enter one of the options. Do not enter the vertical bar.	`{ENABLE \| DISABLE}` `[COMPRESS \| NOCOMPRESS]`
`...`	Horizontal ellipsis points indicate either: That we have omitted parts of the code that are not directly related to the example That you can repeat a portion of the code	`CREATE TABLE ... AS` `subquery``;` `SELECT` `col1``,` `col2``, ... ,` `coln` `FROM employees;`
. . .	Vertical ellipsis points indicate that we have omitted several lines of code not directly related to the example.	`SQL> SELECT NAME FROM V$DATAFILE;` `NAME` `-----------------------------------` `/fsl/dbs/tbs_01.dbf` `/fs1/dbs/tbs_02.dbf` `.` `.` `.` `/fsl/dbs/tbs_09.dbf` `9 rows selected.`
Other notation	You must enter symbols other than brackets, braces, vertical bars, and ellipsis points as shown.	`acctbal NUMBER(11,2);` `acct CONSTANT NUMBER(4) := 3;`
`Italics`	Italicized text indicates placeholders or variables for which you must supply particular values.	`CONNECT SYSTEM/``system_password` `DB_NAME =` `database_name`
`UPPERCASE`	Uppercase typeface indicates elements supplied by the system. We show these terms in uppercase in order to distinguish them from terms you define. Unless terms appear in brackets, enter them in the order and with the spelling shown. However, because these terms are not case sensitive, you can enter them in lowercase.	`SELECT last_name, employee_id FROM employees;` `SELECT * FROM USER_TABLES;` `DROP TABLE hr.employees;`
`lowercase`	Lowercase typeface indicates programmatic elements that you supply. For example, lowercase indicates names of tables, columns, or files. Note: Some programmatic elements use a mixture of UPPERCASE and lowercase. Enter these elements as shown.	`SELECT last_name, employee_id FROM employees;` `sqlplus hr/hr` `CREATE USER mjones IDENTIFIED BY ty3MU9;`

Documentation Accessibility

Our goal is to make Oracle products, services, and supporting documentation accessible, with good usability, to the disabled community. To that end, our documentation includes features that make information available to users of assistive technology. This documentation is available in HTML format, and contains markup to facilitate access by the disabled community. Standards will continue to evolve over time, and Oracle Corporation is actively engaged with other market-leading technology vendors to address technical obstacles so that our documentation can be accessible to all of our customers. For additional information, visit the Oracle Accessibility Program Web site at

http://www.oracle.com/accessibility/

Accessibility of Code Examples in Documentation

JAWS, a Windows screen reader, may not always correctly read the code examples in this document. The conventions for writing code require that closing braces should appear on an otherwise empty line; however, JAWS may not always read a line of text that consists solely of a bracket or brace.

Accessibility of Links to External Web Sites in Documentation

This documentation may contain links to Web sites of other companies or organizations that Oracle Corporation does not own or control. Oracle Corporation neither evaluates nor makes any representations regarding the accessibility of these Web sites.