Oracle SQL - Introduction Functions


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:

  • Numeric functions
  • Alphanumeric functions
  • Group functions
  • Date functions
  • Conversion functions
  • Other functions

T?he following table lists some examples of SQL functions.

Function Explanation
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.