单项选择题

A. All of the desired resultsB. Two of the desired resu……

The EMPLOYEES table contains these columns:
LAST_NAME VARCHAR2 (25)
SALARY NUMBER (6,2)
COMMISSION_PCT NUMBER (6)
You need to write a query that will produce these results:
1. Display the salary multiplied by the commission_pct.
2. Exclude employees with a zero commission_pct.
3. Display a zero for employees with a null commission value. Evaluate the SQL statement:
SELECT LAST_NAME, SALARY*COMMISSION_PCT FROM EMPLOYEES
WHERE COMMISSION_PCT IS NOT NULL;
What does the statement provide? （）

A. All of the desired results
B. Two of the desired results
C. One of the desired results
D. An error statement

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热门试题

单项选择题A subquery can be used to （）.

A. Create groups of data
B. Sort data in a specific order
C. Convert data to a different format
D. Retrieve data based on an unknown condition

单项选择题Which clause should you use to exclude group results? （）

A. WHERE
B. HAVING
C. RESTRICT
D. GROUP BY
E. ORDER BY

单项选择题What is true about joining tables through an equijoin? （）

A. You can join a maximum of two tables through an equijoin.
B. You can join a maximum of two columns through an equijoin.
C. You specify an equijoin condition in the SELECT or FROM clauses of a SELECT statement.
D. To join two tables through an equijoin, the columns in the join condition must be primary key and foreign key columns.
E. You can join n tables (all having single column primary keys) in a SQL statement by specifying a minimum of n-1 join conditions.

单项选择题You need to calculate the total of all salaries in the accounting department. Which group function should you use? （）

A. MAX
B. MIN
C. SUM
D. COUNT
E. TOTAL
F. LARGEST

单项选择题You define a multiple-row subquery in the WHERE clause of an SQL query with a comparison operator = . What happens when the main query is executed? （）

A. The main query executes with the first value returned by the subquery.
B. The main query executes with the last value returned by the subquery.
C. The main query executes with all the values returned by the subquery.
D. The main query fails because the multiple-row subquery cannot be used with the comparison operator.
E. You cannot define a multiple-row subquery in the WHERE clause of a SQL query.