Answer:
//here is code in java.
import java.util.*;
class Solution
{
// main method of class
public static void main (String[] args) throws java.lang.Exception
{
try{
// declare an initialize first string variables
String st1="hello";
// declare an initialize first string variables
String st2="world";
// create another string variable
String st3;
// exchange the value of both string variables
st3=st1;
st1=st2;
st2=st3;
System.out.println("value of first String after exchange: "+st1);
System.out.println("value of second String after exchange: "+st2);
}catch(Exception ex){
return;}
}
}
Explanation:
declare and initialize two string variables.Create another string variable "st3". first assign value of "st1" to "st3" after then value of "st2" to "st1" and then assign value of "st3" to "st2". This will exchange the values of both the string.
Output:
value of first String after exchange: world
value of second String after exchange: hello
Nested
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Answer: Limits the row data that are returned.
Explanation: In structured query language (SQL), The where clause is used as a filter. The filter is applied to a column and as such the filter value or criteria determines the values that are spared in the column on which the WHERE clause is applied. All rows in which the column value does not meet the WHERE clause criteria are exempted from the output. This will hence limit the number of rows which our command displays.
For instance,
FROM * SELECT table_name WHERE username = 'fichoh' ;
The command above filters the username column for username with fichoh, then displays only rows of Data with fichoh as the username. All data columns are displayed but rows of data which do not match fichoh are exempted.
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