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