Update SQL quary with if condition

PHP
5

in database table field value is not updating values, its remain same , not showing any error massege ,

if($meanduration > 120){
mysql_query(“UPDATE table_name SET column_name = ‘3’ WHERE column_name=‘value’”);
}
elseif($meanduration < 119)
{
mysql_query(“UPDATE table_name SET column_name =‘0’ WHERE coulmn_name
=‘value’”);
}

my problem is value is not updating in data base , $meanduration result is 55.33 , in data base sql is not executing
but if i give any string in the execution place of “if” and “else” condition insted of sql query its giving me right ans , why sql query is not execute and not replacing the value while i reload the page