MYSQLコマンドのクリーンアップ

SELECT * FROM tablename 	# 전체 item 반환
SELECT column1, column2 FROM tablename

SELECT * FROM tablename ORDER BY column1 ASC		# c1 기준 오름차순 정렬
SELECT * FROM tablename ORDER BY column2 DESC		# c2 기준 내림차순 정렬
SELECT * FROM tablename ORDER BY column1 ASC, column2 DESC

SELECT * FROM tablename WHERE column1='cond' 		# c1이 cond인 item 반환 

SELECT * FROM tablename ORDER BY column1 ASC LIMIT n	# n개만 반환

SELECT MIN(column1) FROM tablename 
SELECT MAX(column2) FROM tablename 

SELECT COUNT(*) FROM tablename 				# 전채 행 갯수
SELECT COUNT(column1) FROM tablename 		# c1 데이터 갯수

SELECT DISTINCT(column1) FROM tablename
SELECT COUNT(DISTINCT(column1)) FROM tablename 

SELECT column1 COUNT(*) FROM tablename GROUP BY(column1) 	
# c1 기준으로 그룹화 해서 각 item이 몇 개씩 있나 반환

SELECT column1 COUNT(*) FROM tablename GROUP BY(column1) HAVING COUNT(*)>1
# c1 기준으로 그룹화 해서 그룹의 아이템이 2개 이상일 때만 각 item이 몇 개씩 있나 반환

SELECT * FROM tablename WHERE NOT (column1) IS NULL
SELECT colum1 AS c1, colum2 AS c2 FROM tablename

YEAR(DATETIME)
MONTH(DATETIME)
HOUR(DATETIME)

SELECT COALESCE(column1, 'no') FROM tableNAME
SELECT COALESCE(column1, column2, 'nono') FROM tableNAME
# c1이 null이면 c2, c2도 null이면 'nono'

SELECT column1 FROM tableNAME
WHERE column1 IN ('case1', 'case2', 'case3')

SELECT column1 FROM tableNAME
WHERE LOWER(column1) LIKE '%something%'