Which two statements are true regarding the USING clause in table joins?（）A、It can be used to join a maximum of three tables B、It can be used to restrict the number of columns used in a NATURAL join C、It can be used to access data from tables through equi

第1题：

Which of the following statements is true regarding the VERSIONS BETWEEN clause？（）  

• A、 The VERSIONS BETWEEN clause may be used in DML statements.
• B、 The VERSIONS BETWEEN clause may be used in DDL statements.
• C、 The VERSIONS BETWEEN clause may not be used to query past DDL changes to tables.
• D、 The VERSIONS BETWEEN clause may not be used to query past DML statements to tables.

第2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.

第3题：

Which statements are true regarding the Query Result Cache？（） 

• A、 It can be set at the system， session， or table level.
• B、 It is used only across statements in the same session.
• C、 It can store the results from normal as well as flashback queries.
• D、 It can store the results of queries based on normal，temporary，and dictionary tables.

第4题：

Which statements describe the capabilities of the DBMS_NETWORK_ACL_ADMIN package?（）

• A、It can be used to allow the access privilege settings for users but not roles.
• B、It can be used to allow the access privilege settings for users as well as roles.
• C、It can be used to control the time interval for which the access privilege is available to a user.
• D、It can be used to selectively restrict the access for each user in a database to different host computers.
• E、It can be used to selectively restrict a user's access to different applications in a specific host computer.

第5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.

第6题：

Which two statements are true regarding the USING and ON clauses in table joins?（）

• A、Both USING and ON clauses can be used for equijoins and nonequijoins 
• B、Amaximum of one pair of columns can be joined between two tables using the ON clause 
• C、The ON clause can be used to join tables on columns that have different names but compatible data types 
• D、The WHERE clause can be used to apply additional conditions in SELECT statements containing the ON or the USING clause 

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第13题：

Which three statements are true regarding subqueries?（）

• A、Subqueries can contain GROUP BY and ORDER BY clauses 
• B、Main query and subquery can get data from different tables 
• C、Main query and subquery must get data from the same tables 
• D、Subqueries can contain ORDER BY but not the GROUP BY clause 
• E、Only one column or expression can be compared between the main query and subquery
• F、 Multiple columns or expressions can be compared between the main query and subquery

第14题：

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.

第15题：

Which three are true?（）

• A、A MERGE statement is used to merge the data of one table with data from another.
• B、A MERGE statement replaces the data of one table with that of another.
• C、A MERGE statement can be used to insert new rows into a table.
• D、A MERGE statement can be used to update existing rows in a table.

第16题：

Which two statements are true regarding subqueries? （）

• A、A subquery can retrieve zero or more rows 
• B、Only two subqueries can be placed atone level 
• C、A subquery can be used only in SQL query statements 
• D、A subquery can appear on either side of a comparison operator 
• E、There is no limit on the number of subquery levels in the WHERE clause of a SELECT statement 

第17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 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 an INSERT statement to insert multiple rows at a time.

第18题：

What two statements are true regarding the recommendations received from the SQL Access Advisor？（）

• A、 It cannot generate recommendations that support multiple workload queries.
• B、 It can recommend partitioning on tables provided that the workloads have some predicates and joins on the columns of the NUMBER or DATE type.
• C、 It can recommend partitioning only on tables that have at least 10，000 rows.
• D、 It can recommend only B-tree indexes and not bitmap or function-based indexes.

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