Oracle SQL By Example

Chapter 4. Character, Number, and Miscellaneous Functions

Functions are a very useful and powerful part of the SQL language. They can transform data in a way that is different from the way it is stored in a database. A function is a type of formula whose result is one of two things: either a transformation, such as a change in the name of a student to uppercase letters, or information, such as the length of a word in a column. Most functions share similar characteristics, including a name, and typically at least one input parameter, also called an argument, inside a pair of matching parentheses.

function_name(input_parameter) ...