在MySQL中，可以使用以下方式处理NULL值：
SELECT * FROM table_name WHERE column_name IS NULL;
SELECT * FROM table_name WHERE column_name IS NOT NULL;
SELECT COALESCE(column_name, 'replacement_value') FROM table_name;
SELECT IFNULL(column_name, 'replacement_value') FROM table_name;
CREATE TABLE table_name (
column_name VARCHAR(50) DEFAULT NULL
);
UPDATE table_name SET column_name = IFNULL(column_name, 'replacement_value') WHERE condition;
