To add a new column to a table, you use the ALTER TABLE ADD COLUMN statement as follows:. It enables you to create an alias or correlation name that references values in the trigger’s subject table. Summary: in this tutorial, you will learn how to use the SQL ADD COLUMN clause of the ALTER TABLE statement to add one or more columns to an existing table.. Overview of SQL ADD COLUMN clause. Asked: April 20, 2010 - 5:13 pm UTC . Answered by: Tom Kyte - Last updated: August 21, 2017 - 5:38 am UTC. One part of the SQL CREATE TRIGGER syntax that you can use is the optional REFERENCING old_or_new_value_alias_list phrase. SQL> SQL> SQL> select empno, ename, bdate 2 , msal as salary 3 , comm as commission 4 from employees; month month EMPNO last_name BDATE salary salary ----- ----- ----- ----- ----- 1 Jason 18-12-1965 $800.00 null 2 Jerry 19-11-1966 $1600.00 $300.00 3 Jord 21-10-1967 $1700.00 $500.00 4 Mary 22-09-1968 $1800.00 null 5 Joe 23-08-1969 $1900.00 $1400.00 6 Black 24-07-1970 $2000.00 null 7 … Description . This question is . In Oracle, you can create an autonumber field by using sequences. You Asked . Adding a column with a default value to a table; Breadcrumb. Oracle / PLSQL: Sequences (Autonumber) This Oracle tutorial explains how to create and drop sequences in Oracle with syntax and examples. In this example we query for tab_col_name and place it into the my_var_name variable: column tab_col_name new_value my_var_name select tab_col_name from mytab; prompt "Variable value is: &my_var_name" SQL Script Arguments ALTER TABLE table_name ADD [COLUMN] column_definition; . Re: sqlplus substitution variables. Create … From: William Robertson ; To: oracle-l ; Date: Mon, 31 Dec 2007 19:51:36 +0000; You can make use of the behaviour of COLUMN ... NEW_VALUE for queries that return no rows, which is to initialise the corresponding variable without overwriting any existing value.For example, if this is "test_params.sql": The COLUMN CLPPlus command specifies character and numeric output formats for columns in a table. Thanks for the question, Ricardo. SQL*Plus has a new_value argument to the column clause, used to capture SQL results and pass them back as variable in SQL*Plus. Question and Answer. You can change or clear format settings for the same column more than once in the current session. This can be useful when you need to create a unique number to act as a primary key. Formats set by the COLUMN command remain in effect only for the duration of the current session. By Allen G. Taylor . A sequence is an object in Oracle that is used to generate a number sequence. Viewed 100K+ times! Latest Followup. Category: Database - Version: 10.2. In this statement, First, specify the table to …