Oracle functions are built into Oracle and are available for use in various appropriate Oracle statements. You can also create your own function using PL/SQL.
| Function | Description |
|---|---|
| BFILENAME | Returns a BFILE locator for a physical LOB binary file. |
| CARDINALITY | Returns the number of elements in a nested table. |
| CASE | Provides functionality of an IF-THEN-ELSE statement. |
| COALESCE | Returns the first non-null expression in the list. |
| DECODE | Provides functionality of an IF-THEN-ELSE statement. |
| EMPTY_BLOB | To initialize a LOB column to EMPTY in an INSERT statement or UPDATE statement or it can be used initalize a LOB variable. |
| EMPTY_CLOB | To initialize a LOB column to EMPTY in an INSERT statement or UPDATE statement or it can be used initalize a LOB variable. |
| GROUP_ID | To identify duplicated groups in your query results. |
| LNNVL | To evaluate a condition when one of the operands may contain a NULL value. |
| NANVL | To convert Nan (Not a number) values into either NULL or 0. |
| NULLIF | To compares expr1 and expr2 |
| NVL | To substitute a value when a null value is encountered. |
| NVL2 | To substitutes a value when a null value is encountered |
| SYS_CONTEXT | To retrieve information about the Oracle environment. |
| UID | Returns the id number for a user's session. |
| USER | Returns the user_id from the current Oracle session. |
| USERENV | To retrieve information about the current Oracle session. |