SQL NULL Functions

Following SQL Null Functions are discussed in this section. There are FOUR NULL functions used in SQL Database;And the function types mentioned below:

Types of SQL Null Functions

• SQL ISNULL()
• SQL IFNULL()
• SQL COALESCE()
• SQL NVL()

ISNULL Function in SQL

The ISNULL function is used to replace NULL values in SQL Server:

SQL ISNULL() Syntax

SELECT column_name(s),
ISNULL (column_name, value_to_replace)
FROM table_name;

MySQL ISNULL() Syntax

SELECT column_name(s)
FROM table_name
WHERE ISNULL (column_name);

IFNULL Function in SQL

The IFNULL function is used only in MySQL Server. In SQL Server & Oracle, we can't use IFNULL function.

SQL IFNULL() Syntax

SELECT column_name(s),
IFNULL (column_name, value_to_replace)
FROM table_name;

COALESCE Function in SQL

The COALESCE function returns first NON-NULL expression among its arguments in SQL server.

SQL COALESCE() Syntax

SELECT column_name(s),
COALESCE (column_name1, column_name2, column_name3, ...)
FROM table_name;

NVL Function in SQL

The NVL function is available only in Oracle database, it is not available in MySQL or SQL server.

• The NVL function is used to replace NULL value with another value.
• The NVL function is similar to the IFNULL function in MySQL server.