#9 SQL ifnull, if, case 일반함수 사용하기

SELECT name, dept, salary, ifnull(bonus, 0) FROM class_salary;

SELECT name, dept, salary, if(bonus is null, 0, bonus) FROM class_salary;

SELECT name
     , CASE WHEN dept = 'A' THEN '경영지원부'
	        WHEN dept = 'B' THEN '영업부'
			ELSE '회계팀' END AS dept
	 , salary
	 , bonus
FROM class_salary;

SELECT name
     , CASE WHEN dept = 'A' THEN '경영지원부'
	        WHEN dept = 'B' THEN '영업부'
			ELSE '회계팀' END AS dept
	 , salary 
	 , if(salary >= 300, '고액연봉', '일반') as salary_type
	 , ifnull(bonus, 0)
	 , CASE WHEN ifnull(bonus, 0) = 0 THEN '해당없음'
	        ELSE '보너스 해당자' END AS bonus_type
FROM class_salary;