Which statement is true regarding the INTERSECT operator?（）A、It ignores NULL values B、Reversing the order of the intersected tables alters the result C、The names of columns in all SELECT statements must be identical D、The number of columns and data types 

题目

Which statement is true regarding the INTERSECT operator?（）

  • A、It ignores NULL values 
  • B、Reversing the order of the intersected tables alters the result 
  • C、The names of columns in all SELECT statements must be identical 
  • D、The number of columns and data types must be identical for all SELECT statements in the query 
相似考题

1.Which of the following is not among the basic features of a relational database?A．It does not matter what order the rows are in.B．It does not matter what order the columns are in.C．Different columns should have different column names.D．Different columns should have different data types.

2.The EMPLOYEES table has these columns:Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement:What is true about your ALTER statement?()A. Column definitions cannot be altered to add DEFAULT values.B. A change to the DEFAULT value affects only subsequent insertions to the table.C. Column definitions cannot be altered at add DEFAULT values for columns with a NUMBER data type.D. All the rows that have a NULL value for the SALARY column will be updated with the value 5000.

3.Which two statements are true regarding partitioning in Mysql?()A.Tables with BLOB and TEXT columns cannot be partitionedB.Partitioning allows easier management of smaller data sets for certain queriesC.Partitioning allows different columns to be stored in separate filesD.The partitioning expression is an integer or function that returns an integer value or NULL valueE.Partitioning is only available for those storage engines that implements it natively

4.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.

更多“Which statement is true regarding the INTERSECT operator?（）A、It ignores NULL values B、Reversing the order of the intersected tables alters the result C、The names of columns in all SELECT statements must be identical D、The number of columns and data types ”相关问题

  • 第1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 identical column names.

    D.The FROM clause contains two or more tables in the SELECT statement.


    参考答案：C

  • 第2题：

    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 equijoins as well as nonequijoins 
    • D、It can be used to join tables that have columns with the same name and compatible data types

    正确答案:B,D

  • 第3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

    正确答案:A,B,E

  • 第4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.

    正确答案:E

  • 第5题：

    Which two statements are true regarding the ORDER BY clause? （）

    • A、It is executed first in the query execution 
    • B、It must be the last clause in the SELECT statement 
    • C、It cannot be used in a SELECT statement containing a HAVING clause
    • D、You cannot specify a column name followed by an expression in this clause 
    • E、You can specify a combination of numeric positions and column names in this clause

    正确答案:B,E

  • 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 

    正确答案:C,D

  • 第7题：

    In which two cases would you use an outer join? （）

    • A、The tables being joined have NOT NULL columns.
    • B、The tables being joined have only matched data.
    • C、The columns being joined have NULL values.
    • D、The tables being joined have only unmatched data.
    • E、The tables being joined have both matched and unmatched data.
    • F、Only when the tables have a primary key/foreign key relationship.

    正确答案:C,E

  • 第8题：

    多选题
    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


    正确答案： A,C
    解析： 暂无解析

  • 第9题：

    多选题
    In which three cases would you use the USING clause?（）
    A

    You want to create a nonequijoin.

    B

    The tables to be joined have multiple NULL columns.

    C

    The tables to be joined have columns of the same name and different data types.

    D

    The tables to be joined have columns with the same name and compatible data types.

    E

    You want to use a NATURAL join, but you want to restrict the number of columns in the join condition.


    正确答案： C,B
    解析： 暂无解析

  • 第10题：

    单选题
    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.


    正确答案： B
    解析： 暂无解析

  • 第11题：

    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 identical column names.

    D

    The FROM clause contains two or more tables in the SELECT statement.


    正确答案： B
    解析： 暂无解析

  • 第12题：

    多选题
    Which two statements are true regarding the ORDER BY clause? （）
    A

    It is executed first in the query execution

    B

    It must be the last clause in the SELECT statement

    C

    It cannot be used in a SELECT statement containing a HAVING clause

    D

    You cannot specify a column name followed by an expression in this clause

    E

    You can specify a combination of numeric positions and column names in this clause


    正确答案： E,C
    解析： 暂无解析

  • 第13题：

    In which three cases would you use the USING clause?()

    A.You want to create a nonequijoin.

    B.The tables to be joined have multiple NULL columns.

    C.The tables to be joined have columns of the same name and different data types.

    D.The tables to be joined have columns with the same name and compatible data types.

    E.You want to use a NATURAL join, but you want to restrict the number of columns in the join condition.


    参考答案：C, D, E

  • 第14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 identical column names.
    • D、The FROM clause contains two or more tables in the SELECT statement.

    正确答案:C

  • 第15题：

    What is true of using group functions on columns that contain NULL values?（）

    • A、Group functions on columns ignore NULL values.
    • B、Group functions on columns returning dates include NULL values.
    • C、Group functions on columns returning numbers include NULL values.
    • D、Group functions on columns cannot be accurately used on columns that contain NULL values.
    • E、Group functions on columns include NULL values in calculations if you use the keyword INC_NULLS.

    正确答案:A

  • 第16题：

    Which two statements are true regarding partitioning in Mysql?（）

    • A、Tables with BLOB and TEXT columns cannot be partitioned
    • B、Partitioning allows easier management of smaller data sets for certain queries
    • C、Partitioning allows different columns to be stored in separate files
    • D、The partitioning expression is an integer or function that returns an integer value or NULL value
    • E、Partitioning is only available for those storage engines that implements it natively

    正确答案:B,E

  • 第17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.

    正确答案:A,B

  • 第18题：

    The EMPLOYEES table has these columns: LAST_NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATE Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: ALTER TABLE EMPLOYEES MODIFY (SALARY DEFAULT 5000); Which is true about your ALTER statement?（）

    • A、Column definitions cannot be altered to add DEFAULT values.
    • B、A change to the DEFAULT value affects only subsequent insertions to the table.
    • C、Column definitions cannot be altered to add DEFAULT values for columns with a NUMBER data type.
    • D、All the rows that have a NULL value for the SALARY column will be updated with the value 5000.

    正确答案:B

  • 第19题：

    多选题
    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 equijoins as well as nonequijoins

    D

    It can be used to join tables that have columns with the same name and compatible data types


    正确答案： A,C
    解析： 暂无解析

  • 第20题：

    单选题
    View the Exhibit and examine the structure of the ORDERS and ORDERJTEMS tables.  Evaluate the following SQL statement：   SELECT oi.order_id， product_jd， order_date   FROM order_items oi JOIN orders o   USING （order_id）；   Which statement is true regarding the execution of this SQL statement？（）
    A

     The statement would not execute because table aliases are not allowed in the JOIN clause.

    B

     The statement would not execute because the table alias prefix is not used in the USING clause.

    C

     The statement would not execute because all the columns in the SELECT clause are not prefixed with table aliases.

    D

     The statement would not execute because the column part of the USING clause cannot have a qualifier in the SELECT list.


    正确答案： A
    解析： 暂无解析

  • 第21题：

    多选题
    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.


    正确答案： D,E
    解析： 暂无解析

  • 第22题：

    单选题
    Which statement is true regarding the INTERSECT operator?（）
    A

    It ignores NULL values 

    B

    Reversing the order of the intersected tables alters the result 

    C

    The names of columns in all SELECT statements must be identical 

    D

    The number of columns and data types must be identical for all SELECT statements in the query 


    正确答案： D
    解析： 暂无解析

  • 第23题：

    多选题
    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


    正确答案： B,D
    解析： 暂无解析

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