1Z0-007多項(xiàng)選擇題每日一練(2019.12.11)

A. A single row subquery can retrieve only one column and one row.
B. A single row subquery can retrieve only one row but many columns.
C. A multiple row subquery can retrieve multiple rows and multiple columns.
D. A multiple row subquery can be compared by using the ">" operator.
E. A single row subquery can use the IN operator.
F. A multiple row subquery can use the "=" operator.

A. TRIM
B. REPLACE
C. TRUNC
D. TO_DATE
E. MOD
F. CASE

A.The sort is in ascending by order by default.
B.The sort is in descending order by default.
C.The ORDER BY clause must precede the WHERE clause.
D.The ORDER BY clause is executed on the client side.
E.The ORDER BY clause comes last in the SELECT statement.
F.The ORDER BY clause is executed first in the query execution.

A.Constraints provide data independence.
B.Constraints make complex queries easy.
C.Constraints enforce rules at the view level.
D.Constraints enforce rules at the table level.
E.Constraints prevent the deletion of a table if there are dependencies.
F.Constraints prevent the deletion of an index if there are dependencies.

A. listing the employees who earn the same amount of commission as employee 3
B. finding the total commission earned by the employees in department 10
C. finding the number of employees who earn a commission that is higher than the average commission of the company
D. listing the departments whose average commission is more that 600
E. listing the employees who do not earn commission and who are working for department 20 in descending order of the employee ID 
F. listing the employees whose annual commission is more than 6000