https://blog.gongquiz.com/2024/04/14/sqlstructured-query-language%ec%9d%98-%eb%8d%b0%ec%9d%b4%ed%84%b0-%ec%a1%b0%ec%9e%91%eb%ac%b8dml%ec%97%90-%ed%95%b4%eb%8b%b9%ed%95%98-%ec%b8%a1%eb%9f%89%eb%b0%8f%ec%a7%80%ed%98%95%ea%b3%b5-2/