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。
第1题:
SQLServer中左联接查询用left join,Oracle中用什么?
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()。
第3题:
What is true regarding subqueries?()
第4题:
下列连接中能自动删除重复的列是()。
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?()
第6题:
铰制孔用螺栓可用于外载荷为().
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?()
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。
第9题:
A inner join B
A left join B
A right join B
Across join B
第10题:
new Inner(); // At line 3
new Inner(); // At line 8
new o.Inner(); // At line 8
new Outer.Inner(); // At line 8
第11题:
Compilation fails.
An instance of the Inner class can be constructed with “new Outer.Inner()”.
An instance of the Inner class cannot be constructed outside of package foo.
An instance of the Inner class can be constructed only from within the Outer class.
From within the package foo, and instance of the Inner class can be constructed with “new Inner()”.
第12题:
对
错
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。
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?()
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?()
第16题:
package foo; public class Outer ( public static class Inner ( ) ) Which statement is true? ()
第17题:
要求传递载荷特别大、定心精度高的轴毂联接宜用()
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()
第19题:
在SQL-SELECT语句中,设置内部联接的命令是()。
第20题:
What is true regarding subqueries?()
第21题:
The inner query always sorts the results of the outer query
The outer query always sorts the results of the inner query
The outer query must return a value to the outer query
The inner query returns a value to the outer query
The inner query must always return a value or the outer query will give an error
第22题:
An instance of the Inner class can be constructed with “new Outer.Inner ()”
An instance of the inner class cannot be constructed outside of package foo.
An instance of the inner class can only be constructed from within the outer class.
From within the package bar, an instance of the inner class can be constructed with “new inner()”
第23题:
Member variables of the outer instance are always accessible to inner instances, regardless of their accessibility modifiers.
Member variables of the outer instance can never be referred to using only the variable name within the inner instance.
More than one inner instance can be associated with the same outer instance.
All variables from the outer instance that should be accessible in the inner instance must be declared final.
A class that is declared final cannot have any inner classes.
第24题:
The inner query always sorts the results of the outer query.
The outer query always sorts the results of the inner query.
The outer query must return a value to the inner query.
The inner query returns a value to the outer query.
The inner query must always return a value or the outer query will give an error.