更多“pgSQL中内联接用INNER而外联接用OUTER,默认为INNER;LEFT、RIGHT、FULL均隐含外联接。”相关问题
  • 第1题:

    SQLServer中左联接查询用left join,Oracle中用什么?


    正确答案:

     

    左连接:select(nvl(a.c,0)-nvl(b.c,0)) from a,b where a.id(+)=b.id
    右连接:select(nvl(a.c,0)-nvl(b.c,0)) from a,b where a.id=b.id(+)
    自连接:select(nvl(a.c,0)-nvl(b.c,0)) from a,b where a.id(+)=b.id(+)
    说明:加号写在左就是左连接,写在右就是右连接,看加号的方法来定

  • 第2题:

    关于HQL的连接查询,说法错误的是()。

    • A、inner join 或 join用于内连接
    • B、inner join fetch或 join fetch用于迫切内连接
    • C、left outer join fetch 或 left join fetch用于迫切左外连接
    • D、right outer join fetch 或 right join fetch用于迫切右外连接

    正确答案:D

  • 第3题:

    What is true regarding subqueries?()

    • A、The inner query always sorts the results of the outer query
    • B、The outer query always sorts the results of the inner query
    • C、The outer query must return a value to the outer query
    • D、The inner query returns a value to the outer query
    • E、The inner query must always return a value or the outer query will give an error

    正确答案:D

  • 第4题:

    下列连接中能自动删除重复的列是()。

    • A、INNER JOIN
    • B、LEFT OUTER JOIN
    • C、RIGHT OUTER JOIN
    • D、FULL OUTER JOIN

    正确答案:A

  • 第5题:

    齿轮减速器的箱体和箱盖用螺纹联接,箱体被联接处的厚度不太大,且经常拆装,一般用什么联接?()

    • A、螺栓联接
    • B、螺钉联接
    • C、双头螺柱联接

    正确答案:A

  • 第6题:

    铰制孔用螺栓可用于外载荷为().

    • A、轴向载荷和横向载荷的联接中
    • B、横向载荷和弯矩的联接中
    • C、横向载荷和扭矩联接中

    正确答案:C

  • 第7题:

    以下哪两组联接关键字可以创建这样一个联接,该联接包括SELECT语句中指定的第一个表中的不匹配行?()

    • A、LEFT OUTER JOIN和FULL OUTER JOIN
    • B、RIGHTOUTERJOIN和LEFT OUTER JOIN
    • C、USING和HAVING
    • D、OUTER JOIN和USING

    正确答案:A

  • 第8题:

    不论用哪种联接方法联接带条,对皮带运输情况均使用效果相同。


    正确答案:错误

  • 第9题:

    单选题
    对于表A(col1 int,col2 char(1)),表B(col1 int,col2char(1)),为确保表A的数据全部被保留,下面正确的联接方式是()
    A

    A inner join B

    B

    A left join B

    C

    A right join B

    D

    Across join B


    正确答案: B
    解析: 暂无解析

  • 第10题:

    单选题
    1. public class Outer{  2. public void someOuterMethod() {  3. // Line 3  4. }  5. public class Inner{}  6. public static void main( String[]argv ) {  7. Outer o = new Outer();  8. // Line 8  9. }  10. }  Which instantiates an instance of Inner?()
    A

     new Inner(); // At line 3

    B

     new Inner(); // At line 8

    C

     new o.Inner(); // At line 8

    D

     new Outer.Inner(); // At line 8


    正确答案: D
    解析: 暂无解析

  • 第11题:

    单选题
    package foo;  public class Outer {  public static class Inner {  }  }   Which statement is true?()
    A

     Compilation fails.

    B

     An instance of the Inner class can be constructed with “new Outer.Inner()”.

    C

     An instance of the Inner class cannot be constructed outside of package foo.

    D

     An instance of the Inner class can be constructed only from within the Outer class.

    E

     From within the package foo, and instance of the Inner class can be constructed with “new Inner()”.


    正确答案: D
    解析: 暂无解析

  • 第12题:

    判断题
    不论用哪种联接方法联接带条,对皮带运输情况均使用效果相同。
    A

    B


    正确答案:
    解析: 暂无解析

  • 第13题:

    使用下列()命令可以使结果表中除了匹配行外,还包括右表有的但左表中不匹配的行。

    • A、LEFT OUTER JOIN
    • B、RIGHT OUTER JOIN
    • C、NATURAL JOIN
    • D、INNER JOIN

    正确答案:B

  • 第14题:

    1. public class Outer{  2. public void someOuterMethod() {  3. // Line 3  4. }  5. public class Inner{}  6. public static void main( String[]argv ) {  7. Outer o = new Outer();  8. // Line 8  9. }  10. }  Which instantiates an instance of Inner?()  

    • A、 new Inner(); // At line 3
    • B、 new Inner(); // At line 8
    • C、 new o.Inner(); // At line 8
    • D、 new Outer.Inner(); // At line 8

    正确答案:A

  • 第15题:

    使用下列哪个命令可以使结果表中除了匹配行外,还包括右表有的但左表中不匹配的行?()

    • A、LEFT OUTER JOIN
    • B、RIGHT OUTER JOIN
    • C、NATURAL JOIN
    • D、INNER JOIN

    正确答案:B

  • 第16题:

    package foo; public class Outer (  public static class Inner (  )  )   Which statement is true? () 

    • A、 An instance of the Inner class can be constructed with “new Outer.Inner ()”
    • B、 An instance of the inner class cannot be constructed outside of package foo.
    • C、 An instance of the inner class can only be constructed from within the outer class.
    • D、 From within the package bar, an instance of the inner class can be constructed with “new inner()”

    正确答案:A

  • 第17题:

    要求传递载荷特别大、定心精度高的轴毂联接宜用()

    • A、切向键联接
    • B、半圆键联接
    • C、平键联接
    • D、花键联接

    正确答案:D

  • 第18题:

    对于表A(col1 int,col2 char(1)),表B(col1 int,col2char(1)),为确保表A的数据全部被保留,下面正确的联接方式是()

    • A、A inner join B
    • B、A left join B
    • C、A right join B
    • D、Across join B

    正确答案:B

  • 第19题:

    在SQL-SELECT语句中,设置内部联接的命令是()。

    • A、INNER JOIN
    • B、LEFT JOIN
    • C、RIGHT JOIN
    • D、FULL JOIN

    正确答案:A

  • 第20题:

    What is true regarding subqueries?()

    • A、The inner query always sorts the results of the outer query.
    • B、The outer query always sorts the results of the inner query.
    • C、The outer query must return a value to the inner query.
    • D、The inner query returns a value to the outer query.
    • E、The inner query must always return a value or the outer query will give an error.

    正确答案:D

  • 第21题:

    单选题
    What is true regarding subqueries?()
    A

    The inner query always sorts the results of the outer query

    B

    The outer query always sorts the results of the inner query

    C

    The outer query must return a value to the outer query

    D

    The inner query returns a value to the outer query

    E

    The inner query must always return a value or the outer query will give an error


    正确答案: B
    解析: 暂无解析

  • 第22题:

    单选题
    package foo; public class Outer (  public static class Inner (  )  )   Which statement is true? ()
    A

     An instance of the Inner class can be constructed with “new Outer.Inner ()”

    B

     An instance of the inner class cannot be constructed outside of package foo.

    C

     An instance of the inner class can only be constructed from within the outer class.

    D

     From within the package bar, an instance of the inner class can be constructed with “new inner()”


    正确答案: D
    解析: 暂无解析

  • 第23题:

    多选题
    Which statements concerning the correlation between the inner and outer instances of non-static inner classes are true?()
    A

    Member variables of the outer instance are always accessible to inner instances, regardless of their      accessibility modifiers.

    B

    Member variables of the outer instance can never be referred to using only the variable name within     the inner instance.

    C

    More than one inner instance can be associated with the same outer instance.

    D

    All variables from the outer instance that should be accessible in the inner instance must be declared     final.

    E

    A class that is declared final cannot have any inner classes.


    正确答案: D,A
    解析: 暂无解析

  • 第24题:

    单选题
    What is true regarding subqueries?()
    A

    The inner query always sorts the results of the outer query.

    B

    The outer query always sorts the results of the inner query.

    C

    The outer query must return a value to the inner query.

    D

    The inner query returns a value to the outer query.

    E

    The inner query must always return a value or the outer query will give an error.


    正确答案: C
    解析: 暂无解析