单项选择题
Which SQL statement returns a numeric value?（）
A.SELECT ADD_MONTHS(MAX(hire_Date), 6) FROM EMP; B.SELECT ROUND(hire_date) FROM EMP; C.SELECT sysdate-hire_date FROM EMP; D.SELECT TO_NUMBER(hire_date + 7) FROM EMP;
多项选择题 Which two statements complete a transaction? （）
多项选择题 Which two statements are true about constraints? （）
单项选择题 What is true about joining tables through an equijoin?（）
