Using SQL*Plus

This topic describes SQL*Plus, Oracle's command line tool for executing SQL and PL/SQL.

Starting and Exiting SQL*Plus

To start SQL*Plus from the operating system command prompt, enter the following:

sqlplus

When prompted, enter the username and password of the user account (schema) that you want to access. For example, enter HR for the username and your_hr_password when prompted.

After you have started SQL*Plus, the SQL> prompt displays for you to type in SQL statements, as follows:

SQL>

When you want to quit or exit SQL*Plus, type EXIT or QUIT at the SQL prompt, as follows:

SQL> EXIT

Displaying Help With SQL*Plus

To display a list of help topics for SQL*Plus commands enter HELP INDEX at the SQL prompt as follows:

SQL> HELP INDEX

From the list of SQL*Plus help topics, you can display help on an individual topic by entering HELP with a topic name. For example the following displays help on the SQL*Plus COLUMN command, which enables you to format column output:

SQL> HELP COLUMN

Entering and Executing SQL Statements and Commands

To enter and execute SQL statements or commands, type in the statement or command at the SQL prompt. At the end of a SQL statement, put a semi-colon (;) and then press the Enter key to execute the statement. For example:

SQL> SELECT * FROM employees;

If the statement does not fit on one line, type in the first line and press the Enter key. Continue entering lines, terminating the last line with a semi-colon (;). For example:


SQL> SELECT employee_id, first_name, last_name
  2  FROM employees
  3  WHERE employee_id >= 105 AND employee_id <= 110;

The output from the previous SELECT statement would be similar to:


EMPLOYEE_ID FIRST_NAME           LAST_NAME
----------- -------------------- -----------------------
        105 David                Austin
        106 Valli                Pataballa
        107 Diana                Lorentz
        108 Nancy                Greenberg
        109 Daniel               Faviet
        110 John                 Chen
6 rows selected.

Note that a terminating semi-colon (;) is optional with SQL *Plus commands, but required with SQL statements.

SQL*Plus DESCRIBE Command

SQL*Plus provides the DESCRIBE to display a description of a database object. For example, the following displays the structure of the employees table. This description is useful when constructing SQL statements that manipulate the employees table.


SQL> DESCRIBE employees
Name                                        Null? Type
---------------------------------------- -------- ------------
EMPLOYEE_ID                              NOT NULL NUMBER(6)
FIRST_NAME                                        VARCHAR2(20)
LAST_NAME                                NOT NULL VARCHAR2(25)
EMAIL                                    NOT NULL VARCHAR2(25)
PHONE_NUMBER                                      VARCHAR2(20)
HIRE_DATE                                NOT NULL DATE
JOB_ID                                   NOT NULL VARCHAR2(10)
SALARY                                            NUMBER(8,2)
COMMISSION_PCT                                    NUMBER(2,2)
MANAGER_ID                                        NUMBER(6)
DEPARTMENT_ID                                     NUMBER(4)

SQL*Plus SET Commands

The SQL*Plus SET commands can be used to specify various SQL*Plus settings, such as the format of the output from SQL*Plus statements. For example, the following SET commands specify the number of lines per page display and the number of characters per line in the output:


SQL> SET PAGESIZE 200
SQL> SET LINESIZE 140

To enable output from PL/SQL blocks with DBMS_OUTPUT

To view all the settings, enter the following at the SQL prompt:

SQL> SHOW ALL

For information about the SQL*Plus SERVEROUTPUT setting to display output from a PL/SQL program, see Inputting and Outputting Data with PL/SQL.


See Also:

  • SQL*Plus User's Guide and Reference for information setting up the SQL*Plus environment with a login file

Running Scripts From SQL*Plus

You can use a text editor to create SQL*Plus script files containing SQL*Plus, SQL, and PL/SQL statements. For consistency, use the .sql extension for the script file name.

A SQL script file is executed with a START or @ command. For example, on a Windows environment you could execute a SQL script as follows:

SQL> @c:\my_scripts\my_sql_script.sql

A SQL script file could be executed on a Linux environment as follows:

SQL> START /home/cjones/my_scripts/my_sql_script.sql

You can use SET ECHO ON to cause a script to echo each statement that is executed. You can use SET TERMOUT OFF to prevent the script output from displaying on the screen.

When running a script, you should include the full path name unless the script is located in the directory where SQL*Plus was launched.

Spooling From SQL*Plus

The SPOOL command can be used to direct the output from SQL*Plus to a disk file, which enables you to save the output for future review.

To start spooling the output to an operating system file, you can enter:

SQL> SPOOL my_log_file.log

If you want to append the output to an existing file:

SQL> SPOOL my_log_file.log APPEND

To stop spooling and close a file, enter the following:

SQL> SPOOL OFF

Using Variables With SQL*Plus

You can write queries that use variables to make your SELECT statements more flexible. You can define the variable prior to running a SQL statement or you can prompt for a variable value at the time that the SQL statement is run.

When using a variable in a SQL statement, the variable name must be begin with an ampersand (&).

This topic includes the following topics:

For information on using bind variables in PL/SQL code, see Using Bind Variables.

Prompting for a Variable

In Example: Defining a Variable, including the variable &emp_id causes the SQL statement to prompt for a value when the statement is executed. You can then enter the employee_id that you want to display, such as employee Id 125.

Defining a Variable

-- prompt for employee_id in a query, you need to enter a valid Id such as 125
SELECT employee_id, last_name, job_id FROM employees WHERE employee_id = &emp_id;

When you run the previous SELECT statement, the output is similar to:


Enter value for emp_id: 125
...
EMPLOYEE_ID LAST_NAME                 JOB_ID
----------- ------------------------- ----------
        125 Nayer                     ST_CLERK

Defining a Variable Value for a Query

In Example: Prompting for a Variable, the variable &jobid is defined prior to running the SQL statement and the defined value is substituted for the variable when the statement is executed.

Prompting for a Variable

-- define a variable value for a query as follows
DEFINE jobid = "ST_CLERK"
-- run a query using the defined value for jobid (ST_CLERK)
SELECT employee_id, last_name FROM employees WHERE job_id = '&jobid';