Given the following query:SELECT last_name, first_name, age, hire_date FROM employee WHERE age > 40Which of the following clauses must be added to return the rows sorted by AGE, oldest first, and by LAST_NAME, from A to Z?()
“雇员”表在LAST_NAME列上有一个名为LN_IDX的索引。您要将此索引更改为FIRST_NAME列的索引。以下哪条SQL语句将实现此操作()
如果希望更新表authors中的first_name列为非空,那么可以使用哪个语句?()
您要对EMPLOYEES表的FIRST_NAME和LAST_NAME列创建一个组合索引。以下哪条语句将完成此任务()