SQL Functions

SQL functions are built into oracle and are available for use in various appropriate SQL statements.
Ø  The SQL functions can be used to…
o   Perform calculations on data
o   Modify individual data items
o   Manipulate output for groups of rows
o   Format dates and numbers for display
o   Convert column data types.
Ø  SQL functions may accept arguments and always return a value, and can be nested.
Ø  If an SQL function is called with a null argument, then null is returned.
SQL Function Types:
SQL identifies two types of functions
Ø  Single row functions
Ø  Multi row functions
Single row functions:
These functions return a single result for every row of a queried table or view.
Ø  Character functions
Ø  Number functions
Ø  Date functions
Ø  Conversion functions
Multi row functions:
These functions manipulate groups of rows and return one result per group of rows.

Ø  Aggregate or group functions