A. Both tables have NULL values.B. You want all unmatch……

单项选择题You added a PHONE_NUMBER column of NUMBER data type to an existing EMPLOYEES table. The EMPLOYEES table already contains records of 100 employees. Now, you want to enter the phone numbers of each of the 100 employees into the table. Some of the employees may not have a phone number available. Which data manipulation operation do you perform? （）

A. MERGE
B. INSERT
C. UPDATE
D. ADD
E. ENTER
F. You cannot enter the phone numbers for the existing employee records.

多项选择题Which two statements about subqueries are true? （）

A. A single row subquery can retrieve data from only one table.
B. A SQL query statement cannot display data from table B that is referred to in its subquery, unless table B is included in the main query's FROM clause.
C. A SQL query statement can display data from table B that is referred to in its subquery, without including table B in its own FROM clause.
D. A single row subquery can retrieve data from more than one table.
E. A single row subquery cannot be used in a condition where the LIKE operator is used for comparison.
F. A multiple-row subquery cannot be used in a condition where the LIKE operator is used for comparison.

多项选择题The ORDERS table has these columns: ORDER_ID NUMBER(4) NOT NULL CUSTOMER_ID NUMBER(12) NOT NULL ORDER_TOTAL NUMBER(10,2) The ORDERS table tracks the Order number, the order total, and the customer to whom the Order belongs. Which two statements retrieve orders with an inclusive total that ranges between 100.00 and 2000.00 dollars? （）

A. SELECT customer_id, order_id, order_total FROM orders RANGE ON order _ total (100 AND 2000) INCLUSIVE;
B. SELECT customer_id, order_id, order_total FROM orders HAVING order _ total BETWEEN 100 and 2000;
C. SELECT customer_id, order_id, order_total FROM orders WHERE order _ total BETWEEN 100 and 2000;
D. SELECT customer_id, order_id, order_total FROM orders WHERE order_total>= 100 and <= 2000;
E. SELECT customer_id, order_id, order_total FROM orders WHERE order_total>= 100 and order_total <= 2000;

单项选择题In a SELECT statement that includes a WHERE clause, where is the GROUP BY clause placed in the SELECT statement? （）

A. Immediately after the SELECT clause
B. Before the WHERE clause
C. Before the FROM clause
D. After the ORDER BY clause
E. After the WHERE clause

多项选择题Which two are true about aggregate functions? （）

A. You can use aggregate functions in any clause of a SELECT statement.
B. You can use aggregate functions only in the column list of the SELECT clause and in the WHERE clause of a SELECT statement.
C. You can mix single row columns with aggregate functions in the column list of a SELECT statement by grouping on the single row columns.
D. You can pass column names, expressions, constants, or functions as parameters to an aggregate function.
E. You can use aggregate functions on a table, only by grouping the whole table as one single group.
F. You cannot group the rows of a table by more than one column while using aggregate functions.