SQL functions are built into the database and are available for use in various appropriate SQL statements. Do not confuse SQL functions with user-defined functions.

If you call a SQL function with an argument of a data type other than the data type expected by the SQL function, then database attempts to convert the argument to the expected data type before performing the SQL function. If you call a SQL function with a null argument, then the SQL function automatically returns null.

• Aggregate Functions
• Character Functions
• Character Functions Returning Number Values
• Conversion Functions
• Date and Time Functions
• Environment and Identifier Functions
• General Comparison Functions
• Large Object Functions
• Null Related Functions
• Numeric Functions
• String Functions