单选题In which of the following situations should correlation names be used?（）A A table referenced in the FROM clause has no indexed column.B The table referenced in the FROM clause has more than 200 columns.C Two or more tables in the FROM clause have ident

第1题：

In which case would you use a FULL OUTER JOIN?（）

• A、Both tables have NULL values.
• B、You want all unmatched data from one table.
• C、You want all matched data from both tables.
• D、You want all unmatched data from both tables.
• E、One of the tables has more data than the other.
• F、You want all matched and unmatched data from only one table.

第2题：

In which four clauses can a subquery be used? （）

• A、in the INTO clause of an INSERT statement
• B、in the FROM clause of a SELECT statement
• C、in the GROUP BY clause of a SELECT statement
• D、in the WHERE clause of a SELECT statement
• E、in the SET clause of an UPDATE statement
• F、in the VALUES clause of an INSERT statement

第3题：

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.

第4题：

Where can subqueries be used?（）

• A、field names in the SELECT statement 
• B、the FROM clause in the SELECT statement 
• C、the HAVING clause in the SELECT statement
• D、the GROUP BY clause in the SELECT statement 
• E、the WHERE clause in only the SELECT statement 
• F、the WHERE clause in SELECT as well as all DML statements

第5题：

In your multitenant container database (CDB) containing pluggable database (PDBs), you granted theCREATE TABLE privilege to the common user C # # A_ADMIN in root and all PDBs. You execute thefollowing command from the root container:SQL > REVOKE create table FROM C # # A_ADMIN;What is the result?（）

• A、It executes successfully and the CREATE TABLE privilege is revoked from C # # A_ADMIN in root only.
• B、It fails and reports an error because the CONTAINER=ALL clause is not used.
• C、It excludes successfully and the CREATE TABLE privilege is revoked from C # # A_ADMIN in root and all PDBs.
• D、It fails and reports an error because the CONTAINER=CURRENT clause is not used.
• E、It executes successfully and the CREATE TABLE privilege is revoked from C # # A_ADMIN in all PDBs.

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第11题：

Which two are true about aggregate functions? （）

• A、You can use aggregate functions in any clause of a SELECT statement.
• B、You can use aggregate functions only in the column list of the select clause and in the WHERE clause of a SELECT statement.
• C、You can mix single row columns with aggregate functions in the column list of a SELECT statement by grouping on the single row columns.
• D、You can pass column names, expressions, constants, or functions as parameter to an aggregate function.
• E、You can use aggregate functions on a table, only by grouping the whole table as one single group.
• F、You cannot group the rows of a table by more than one column while using aggregate functions.

第12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13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14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 

第15题：

In which scenario would index be most useful?（）

• A、The indexed column is declared as NOT NULL.
• B、The indexed columns are used in the FROM clause.
• C、The indexed columns are part of an expression.
• D、The indexed column contains a wide range of values.

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