Appendix B. SQL*Plus Format Elements

Several SQL*Plus commands control data formats using what is called a format specification. A format specification is a string of characters that tells SQL*Plus exactly how to format a number, date, or text string when it is displayed. The most notable of these commands is the COLUMN command, which is used to format columns of output from a SELECT query. Other commands exist as well. The complete list of SQL*Plus commands that accept format specification strings is shown here:

ACCEPT

Prompts the user to enter a value from the keyboard.

COLUMN

Controls various aspects of the way a column of data is displayed.

SET NUMBER

Defines the default display format for numbers .

TTITTE, BTITLE, REPHEADER, REPFOOTER

Allow number format specifications to control the way numbers are formatted in page headers, page footers, report headers, and report footers.

There are three different broad types of values SQL*Plus can format: numbers, character strings, and dates. Not all commands can handle each type. With most commands, you can specify only number and date formats. The COLUMN command is a good example. The ACCEPT command is the only one that allows you to specify a date format string.

Format specification strings are made up of special characters that have meaning to SQL*Plus in the context of formatting a value for display. Numeric format strings, for example, tend to have many 0s, 9s, decimal points, and dollar signs. Date format strings tend to include things like MM, DD, YYYY, etc. Character string formats are the simplest of all because you have only one thing you can influence: length.