3. 함수 NVL,SYSDATE,IN,BETWEEN,IS NULL,LIKE,LOWER,INITCAP,LPAD,TRIM,REPLACE,CEIL,FLOOR,ROUND,TRUNC,MOD,POWER,SIGN,ADD_MONTHS,TO_CHAR
SELECT FIRST_NAME || ‘ ‘ || LAST_NAME AS NAME FROM EMPLOYEES; ||은 CONCAT SELECT SALARY AS “본봉”, SALARY + SALARY * 0.3 AS “보너스”FROM EMPLOYEES; SELECT -SALARY FROM EMPLOYEES; N