How does MySQL handle NULL values?

In MySQL, you can handle NULL values using the following methods:

1. Use the IS NULL and IS NOT NULL operators to check for NULL values.

SELECT * FROM table_name WHERE column_name IS NULL;
SELECT * FROM table_name WHERE column_name IS NOT NULL;

1. Replace NULL values with a specified value using the COALESCE function.

SELECT COALESCE(column_name, 'replacement_value') FROM table_name;

1. Replace NULL values with a specified value using the IFNULL function.

SELECT IFNULL(column_name, 'replacement_value') FROM table_name;

1. Using the DEFAULT keyword in the CREATE TABLE statement to specify the default value of a column as NULL:

CREATE TABLE table_name (
    column_name VARCHAR(50) DEFAULT NULL
);

1. Use the IFNULL function in an UPDATE statement to update a column’s value to a specified value.

UPDATE table_name SET column_name = IFNULL(column_name, 'replacement_value') WHERE condition;