The nested query executes after the outer query returns the row.
The nested query executes first and then the outer query executes.
The outer query executes only once for the result returned by the inner query.
Each row returned by the outer query is evaluated for the results returned by the inner query.
第1题：
A. the use of rowid
B. a GROUP BY clause
C. an ORDER BY clause
D. only an inline view
E. an inline view and an outer query
第2题：
Which three statements are true regarding subqueries?（）
第3题：
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.
第4题：
What is true regarding subqueries?（）
第5题：
Which two statements about subqueries are true? （）
第6题：
Examine the parameter for your database instance:You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan:Identify the reason why the optimizer chose different execution plans.（）
A. The optimizer used a dynamic plan for the query.
B. The optimizer chose different plans because automatic dynamic sampling was enabled.
C. The optimizer used re-optimization cardinality feedback for the query.
D. The optimizer chose different plan because extended statistics were created for the columns used.
第7题：
Examine the parameter for your database instance: You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan: Identify the reason why the optimizer chose different execution plans.（）
第8题：
A.
B.
C.
D. The query fails because the subquery returns more than one row.
E. The query fails because the outer query and the inner query are using different tables.
第9题：
Which three statements about subqueries are true? （）
第10题：
You are using the Database Resource Manager to manage database resources. You created a resource plan directive for the MANAGERS resource consumer group under the SALES_PLAN by using the following statement： SQL>EXEC DBMS_RESOURCE_MANAGER.CREATE_PLAN_DIRECTIVE （PLAN => ’SALES_PLAN’， GROUP_OR_SUBPLAN => ’MANAGERS’， CPU_P1 => 100， CPU_P2 =>0， SWITCH_GROUP => ’CLERKS’， SWITCH_TIME_IN_CALL => 600）； A user， SCOTT， who is assigned to the MANAGERS group， starts a database session and executes a query on the database. What is the outcome if the query takes approximately 15 minutes to complete？（）