calculate BMI and update BMI Column and update BMI in to range in php mysql : 


[database view][1]
i need to calculate BMI and put that value to catagarize in that into  range as( < 18, 18-24.9 )
below shows  my quries  but it is incorrect 
my program is in php mysql

     mysql_query("UPDATE ncd  SET BMI =WeightKG/(HightM*HightM)"); 
	
	mysql_query("UPDATE ncd  SET BMIrage =2 WHERE BMI >18 AND BMI <25  ");
	mysql_query("UPDATE ncd  SET BMIrage = 3 WHERE  BMI >=25 AND BMI<= 30");


  [1]: http://i.stack.imgur.com/D5aWq.png