Oracle has a lot of powerful functions.
SQL functions have a name, followed by one or more arguments (between parentheses) in a comma-separated list.
You can use functions in expressions, in the same way that you can use operators.
These are the six SQL function categories, based on their operand types:
T?he following table lists some examples of SQL functions.
|AVG(MSAL)||The average monthly salary|
|SQRT(16)||The square root of 16|
|LENGTH(INIT)||The number of characters in the INIT column value|
|LOWER(ENAME)||ENAME column value, in lowercase|
|SUBSTR(ENDDATE,4,3)||Three characters of the ENDDATE column value, from the fourth position|
Oracle allows you to create your own SQL functions by using the PL/SQL or Java languages.