[多项选择]Which two statements are true about WHERE and HAVING clauses? （）
A. A WHERE clause can be used to restrict both rows and groups.
B. A WHERE clause can be used to restrict rows only.
C. A HAVING clause can be used to restrict both rows and groups.
D. A HAVING clause can be used to restrict groups only.
E. A WHERE clause CANNOT be used in a query if the query uses a HAVING clause.
F. A HAVING clause CANNOT be used in subqueries.

[多项选择]Which two statements are true about WHERE and HAVING clauses? （）
A. A WHERE clause can be used to restrict both rows and groups.
B. A WHERE clause can be used to restrict rows only.
C. A HAVING clause can be used to restrict both rows and groups.
D. A HAVING clause can be used to restrict groups only.
E. A WHERE clause CANNOT be used in a query of the query uses a HAVING clause.
F. A HAVING clause CANNOT be used in subqueries.

[多项选择]Which two statements about sequences are true?（）
A. You use a NEXTVAL pseudo column to look at the next possible value that would be generated from a sequence, without actually retrieving the value.
B. You use a CURRVAL pseudo column to look at the current value just generated from a sequence, without affecting the further values to be generated from the sequence.
C. You use a NEXTVAL pseudo column to obtain the next possible value from a sequence by actually retrieving the value from the sequence.
D. You use a CURRVAL pseudo column to generate a value from a sequence that would be used for a specified database column.
E. If a sequence starting from a value 100 and incremented by 1 is used by more then one application, then all of these applications could have a value of 105 assigned to their column whose value is being generated by the sequence.
F. You use REUSE clause when creating a sequence to restart the sequence once it generates the maximum value defined for the sequence.

[多项选择]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]Which two statements about views are true? （）
A. A view can be created as read only.
B. A view can be created as a join on two or more tables.
C. A view cannot have an ORDER BY clause in the SELECT statement.
D. A view cannot be created with a GROUP BY clause in the SELECT statement.
E. A view must have aliases defined for the column names in the SELECT statement.

[多项选择]Which three statements about subqueries are true? （）
A. Asinglerowsubquerycanretrieveonlyonecolumnandonerow.
B. Asinglerowsubquerycanretrieveonlyonerowbutmanycolumns.
C. Amultiplerowsubquerycanretrievemultiplerowsandmultiplecolumns.
D. Amultiplerowsubquerycanbecomparedusingthe"；>；"；operator.
E. AsinglerowsubquerycanusetheINoperator.
F. Amultiplerowsubquerycanusethe"；="；operator.