Problem with arduino & ethernet shield which sends temperature to mysql database

Using Arduino Project Guidance
#1

Hello!
Lately I’ve been working on a project with arduino (with ethernet shield) which sends temperature (we’re using Dallas Temperature sensors) to mysql database (named “test”) via php scrpit. Here is the arduino code:

#include <OneWire.h>
#include <DallasTemperature.h>
#include <SPI.h>
#include <Ethernet.h>

byte mac[] = {0x90, 0xA2, 0xDA, 0x00, 0x11, 0xAC };
byte ip[] = { 172, 16, 3, 115 };
byte server[] = { 172, 16, 0, 201 }; // MySQL

#define ONE_WIRE_BUS 8

OneWire oneWire(ONE_WIRE_BUS);

DallasTemperature sensors(&oneWire);

DeviceAddress insideThermometer;

EthernetClient client;


void setup(void)
{
  Ethernet.begin(mac, ip);
  Serial.begin(9600);
  Serial.println("Starting connection to MySQL");
  Serial.println();
  delay(1000);
  
  Serial.println("connecting...");
  
  if (client.connect(server, 80)) {
    Serial.println("connected");
    
   client.println("GET /update_db.php?celsius=36 HTTP/1.0");
   client.println();
  } else {
    Serial.println("connection failed");
  }
  
  sensors.begin();
  Serial.print("Found ");
  Serial.print(sensors.getDeviceCount(), DEC);
  Serial.println(" devices.");

  if (!sensors.getAddress(insideThermometer, 0)) Serial.println("Unable to find address for Device 0"); 
  
  Serial.print("Device 0 Address: ");
  printAddress(insideThermometer);
  Serial.println();

  sensors.setResolution(insideThermometer, 9);
 
}

void printTemperature(DeviceAddress deviceAddress)
{
 
  float tempC = sensors.getTempC(deviceAddress);
  Serial.print("Temp C: ");
  Serial.println(tempC);
  
}

void loop(void)
{ 
  Serial.print("Requesting temperatures...");
  sensors.requestTemperatures(); // Send the command to get temperatures
  Serial.println("DONE");
  printTemperature(insideThermometer);
  delay(2000);  
}


// function to print a device address
void printAddress(DeviceAddress deviceAddress)
{
  for (uint8_t i = 0; i < 8; i++)
  {
    if (deviceAddress[i] < 16) Serial.print("0");
    Serial.print(deviceAddress[i], HEX);
  }
}

And here is PHP script:

<?php

$celsius = $_GET['celsius'];

//Connect to database 

$con = mysql_connect("serveraddress", "username", "Password");
if(!$con)
      
      die('Could not connect: ' .mysql_error());
     
mysql_select_db("test", $con);

mysql_query("INSERT INTO temp(Temperatuur) VALUES ('$celsius')");

mysql_close($con);

?>

The problem is that the variable only saves itself if the command is like client.println("GET /update_db.php?celsius=36 HTTP/1.0"); but I’d like to save the temperature from Dallas sensor.

#2 
   int tempCelcius=36;
   client.print("GET /update_db.php?celsius=");
   client.print(tempCelcius);
   client.println(" HTTP/1.0");
#3