Which two statements are true regarding single row functions

第1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2题：

Which three statements about subqueries are true?（）

• 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.

第3题：

第4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5题：

Which two statements are true regarding L2TP? （）(Choose two.)

• A、Tunnels are initiated by the LAC
• B、Tunnels are initiated by the LNS
• C、By default, subscriber authentication occurs on the LNS
• D、By default, subscriber authentication occurs on the LAC

第6题：

Which four are attributes of single row functions? （）

• A、cannot be nested
• B、manipulate data items
• C、act on each row returned
• D、return one result per row
• E、accept only one argument and return only one value
• F、accept arguments which can be a column or an expression

第7题：

Which two statements are true regarding high-availability chassis clustering？（）

• A、A chassis cluster consists of two devices.
• B、A chassis cluster consists of two or more devices.
• C、Devices participating in a chassis cluster can be different models.
• D、Devices participating in a chassis cluster must be the same models

第8题：

第9题：

Which two statements are true regarding B-tree indexs（）

• A、The leaf blocks in the index are doubly linked.
• B、The leaf node stores a bitmap for each key value.
• C、The rows with NULL value in key columns also have entries in the index.
• D、The deletion of a row from the table causes a logical deletion in index leaf block and the space becomesavailable for the new leaf entry

第10题：

Which three statements are true regarding single-row functions？（）

• A、 They can accept only one argument.
• B、 They can be nested up to only two levels.
• C、 They can return multiple values of more than one data type.
• D、 They can be used in SELECT， WHERE， and ORDER BY clauses.  
• E、 They can modify the data type of the argument that is referenced.
• F、 They can accept a column name， expression， variable name， or a user-supplied constant as arguments.