1. 문자열 자르기: LEFT, RIGHT, SUBSTRING, SUBSTRING_INDEX * LEFT(string, number_of_chars) - 문자열 왼쪽부터 자르기ex) ▶ SELECT LEFT(컬럼명, 5) AS Ex FROM 테이블명; * RIGHT(string, number_of_chars) - 문자열 오른쪽부터 자르기ex)▶ SELECT RIGHT(CustomerName, 5) AS Ex FROM 테이블명; * SUBSTRING(string, start, length) or (string FROM start FOR length) - 문자열 자르기ex) ▶ SELECT SUBSTRING(컬럼명, 2, 5) AS ExtractString FROM 테이블명;▶ SELECT SUBSTRING..