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Query speed and expressions with constant value


Query speed and expressions with constant value

By : Tzvika Shoham
Date : December 01 2020, 04:55 PM
like below fixes the issue it will be the same performance with a constant expression like 2*2. However if you start comparing ID/2 = 2. It will slow down the query because it has to calculate for all rows.
code :


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A Switch Java problem : case expressions must be constant expressions

A Switch Java problem : case expressions must be constant expressions


By : Nick Munoz
Date : March 29 2020, 07:55 AM
help you fix your problem So it can be evaluated during the compilation phase ( statically check )
See: http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.11 for a formal definition of the switch.
code :
class Switch {
  void x(int n ) {
    switch( n ) {
      case 1: System.out.println("one"); break;
      case 9: System.out.println("nine"); break;
      default:  System.out.println("nothing"); break;
    }
  }
}
C:\>javap -c Switch
Compiled from "Switch.java"
class Switch extends java.lang.Object{
Switch();
  Code:
   0:   aload_0
   1:   invokespecial   #1; //Method java/lang/Object."<init>":()V
   4:   return

void x(int);
  Code:
   0:   iload_1
   1:   lookupswitch{ //2
                1: 28;
                9: 39;
                default: 50 }
   28:  getstatic       #2; //Field java/lang/System.out:Ljava/io/PrintStream;
   31:  ldc     #3; //String one
   33:  invokevirtual   #4; //Method java/io/PrintStream.println:(Ljava/lang/String;)V
   36:  goto    58
   39:  getstatic       #2; //Field java/lang/System.out:Ljava/io/PrintStream;
   42:  ldc     #5; //String nine
   44:  invokevirtual   #4; //Method java/io/PrintStream.println:(Ljava/lang/String;)V
   47:  goto    58
   50:  getstatic       #2; //Field java/lang/System.out:Ljava/io/PrintStream;
   53:  ldc     #6; //String nothing
   55:  invokevirtual   #4; //Method java/io/PrintStream.println:(Ljava/lang/String;)V
   58:  return

}
 1:   lookupswitch{ //2
            1: 28;
            9: 39;
            default: 50 }
   39:  getstatic       #2; //Field java/lang/System.out:Ljava/io/PrintStream;
   42:  ldc     #5; //String nine
   44:  invokevirtual   #4; //Method java/io/PrintStream.println:(Ljava/lang/String;)V
   47:  goto    58
   58:  return
Is it possible to optimize a SELECT COUNT(*) query using a filtered index as a hint to achieve constant speed?

Is it possible to optimize a SELECT COUNT(*) query using a filtered index as a hint to achieve constant speed?


By : Darrington Bevins
Date : March 29 2020, 07:55 AM
like below fixes the issue It seems like what I'm wanting isn't possible. The best answer was left in the comments by Nikola Markovinović which is to forget about the filtered index and use an indexed view instead:
code :
CREATE VIEW [dbo].vw_Orders_TotalShippedNonUrgent WITH SCHEMABINDING 
AS 
SELECT COUNT_BIG(*) AS TotalOrders 
  FROM dbo.Orders WHERE IsUrgent = 0 AND Status = 1;
CREATE UNIQUE CLUSTERED INDEX IX_vw_Orders_TotalShippedNonUrgent ON vw_Orders_TotalShippedNonUrgent(TotalOrders);
Switch - case expressions must be constant expressions, I can't make the if-else statment

Switch - case expressions must be constant expressions, I can't make the if-else statment


By : deleonant
Date : March 29 2020, 07:55 AM
it fixes the issue Take a look at the official blog post about this:
http://tools.android.com/recent/switchstatementconversion
code :
int id = view.getId();
if (id == R.id.button1) {
    action1();
} else if (id == R.id.button2) {
    action2();
} else if (id == R.id.button3) {
    action3();
}
case expressions must be constant expressions error when using map types in optionMenu

case expressions must be constant expressions error when using map types in optionMenu


By : user2916571
Date : March 29 2020, 07:55 AM
hop of those help? The issue is that all of your R.id values are not actually final as they should be. In your R file, you'd find that they are something like public static int sample=0x7f035054;.
The solution to that issue is using if statements. The code you have provided the second time SHOULD work. You can't possibly be getting an "case expressions must be constant expressions" if you had removed the switch statement and used those if statements instead.
Switch statement eclipse error: case expressions must be constant expressions

Switch statement eclipse error: case expressions must be constant expressions


By : melodz dumay crisost
Date : March 29 2020, 07:55 AM
This might help you I wrote a program that would output a flower based off the color I will input. In the switch statement, I keep seeing an error stating that the "case expressions must be constant expressions." I don't see where I am doing it wrong. I'm also having an issue of printing out the plural tense of the flower (if the user would input 2 or higher). , Mark the variables red, purple, etc, as final.
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