Oracle Built in Functions

There are two types of functions in Oracle.

1) Single Row Functions: Single row or Scalar functions return a value for every row that is processed in a query.
2) Group Functions: These functions group the rows of data based on the values returned by the query. This is discussed in SQL GROUP Functions. The group functions are used to calculate aggregate values like total or average, which return just one total or one average value after processing a group of rows.

There are four types of single row functions. They are:
1) Numeric Functions: These are functions that accept numeric input and return numeric values.
2) Character or Text Functions: These are functions that accept character input and can return both character and number values.
3) Date Functions: These are functions that take values that are of datatype DATE as input and return values of datatype DATE, except for the MONTHS_BETWEEN function, which returns a number.
4) Conversion Functions: These are functions that help us to convert a value in one form to another form. For Example: a null value into an actual value, or a value from one datatype to another datatype like NVL, TO_CHAR, TO_NUMBER, TO_DATE etc.

You can combine more than one function together in an expression. This is known as nesting of functions.

What is a DUAL Table in Oracle?
This is a single row and single column dummy table provided by oracle. This is used to perform mathematical calculations without using a table.

Output:

Output:

1) Numeric Functions:

The following examples explains the usage of the above numeric functions

These functions can be used on database columns.

For Example: Let's consider the product table used in sql joins. We can use ROUND to round off the unit_price to the nearest integer, if any product has prices in fraction.

2) Character or Text Functions:

Character or text functions are used to manipulate text strings. They accept strings or characters as input and can return both character and number values as output.

Few of the character or text functions are as given below:

For Example, we can use the above UPPER() text function with the column value as follows.

The following examples explains the usage of the above character or text functions

3) Date Functions:

These are functions that take values that are of datatype DATE as input and return values of datatypes DATE, except for the MONTHS_BETWEEN function, which returns a number as output.

Few date functions are as given below.

The below table provides the examples for the above functions

4) Conversion Functions:

These are functions that help us to convert a value in one form to another form. For Ex: a null value into an actual value, or a value from one datatype to another datatype like NVL, TO_CHAR, TO_NUMBER, TO_DATE.

Few of the conversion functions available in oracle are:

The below table provides the examples for the above functions