I'm trying to do the following:

Find and print 5 closest objects (represented as 3 numbers) to the given object

database = dbnumbers
table = numbers

One object is represented as:

4 fields (id, C1, C2, C3)
id = INT
C1 = FLOAT
C2 = FLOAT
C3 = FLOAT

C1, C2, C3 are random numbers 0-100

Required object is represented as 3 float values:

certain_number1
certain_number2
certain_number3


1. step

Find the closest numbers to the certain_number1 from a numbers table (field C1)
condition: ABS( C1 - certain_number1 ) <= threshold_value

2. step

Between a list of numbers that are seperated by step 1,
pull of the closest numbers to the certain_number2 from a numbers table (field C2)
condition: ABS( C2 - certain_number2 ) <= threshold_value

3. step

Between a list of numbers that are seperated by step 2,
pull of the closest numbers to the certain_number3 from a numbers table (field C3)
condition: ABS( C3 - certain_number3 ) <= threshold_value


Print object whit appropriate values (id, C1, C2, C3)..


Selecting closest values in MySQL:
http://www.techfounder.net/2009/02/02/selecting-closest-values-in-mysql/


Here is code for creating dbnumbers database:

1. import de.bezier.data.sql.*;
   
   MySQL msql;
   
   float c_1, c_2, c_3;
   
   void setup()
   {
       size( 100, 100 );
   
       String user     = "root";
       String pass     = "admin";
       String database = "dbnumbers";
       String table    = "numbers";
       msql = new MySQL( this, "localhost:3306", database, user, pass );
      
       if ( msql.connect() )
       {  
           // create a table with an id, C1, C2, C3
           msql.execute( "CREATE TABLE IF NOT EXISTS " + table + " ("+"id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, C1 DECIMAL (5,2), C2 DECIMAL (5,2), C3 DECIMAL (5,2))");
                      
           // fill the table with some data
           for(int i=0; i<100; i++){
               c_1 = random(100);
               c_2 = random(100);
               c_3 = random(100);
               msql.execute( "INSERT INTO " + table + " (C1, C2 , C3) VALUES (\"" + c_1 + "\", \"" + c_2 + "\", \"" + c_3 + "\")" );
           }
   
           // need to find out how many rows there are in table?
           msql.query( "SELECT COUNT(*) FROM " + table );
           msql.next();
           println( "number of rows: " + msql.getInt(1) );
       }
       else
       {
           // connection failed !
           println("connection failed!");
       }
   }
   
   void draw()
   {
       // ...
   }