NVL vs COALESCE

 NVL vs COALESCE to handle NULL values in SQL.

Both NVL and COALESCE are used in SQL to handle null values, but they have some differences:

Syntax: NVL takes two arguments, while COALESCE takes two or more arguments.

Return value: NVL returns the first argument if it is not null, otherwise it returns the second argument. COALESCE returns the first non-null value from its arguments.

Here are some examples to illustrate the differences:

NVL Example:


SELECT NVL(NULL, 'hello') FROM dual;
This will return 'hello', since the first argument is null.


SELECT NVL('world', 'hello') FROM dual;
This will return 'world', since the first argument is not null.

COALESCE Example:

SELECT COALESCE(NULL, NULL, 'hello', 'world') FROM dual;

This will return 'hello', since it is the first non-null value.


SELECT COALESCE(NULL, 'hello', 'world') FROM dual;
This will also return 'hello', since it is the first non-null value.

Hope it helps.

#sql #null #handling