How do I get data from mysql to Arduino?

Using Arduino Interfacing w/ Software on the Computer
1 
#include <Ethernet.h>
#include <MySQL_Connection.h>
#include <MySQL_Cursor.h>
#include <avr/pgmspace.h>


int SensorPin1 = A0; //analog pin 0
int SensorPin2 = A1; //analog pin 0
int SensorPin3 = A2; //analog pin 0

byte mac_addr[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };  
 
IPAddress server_addr(***);  // mysql 서버 주소를 입력
char user[] = "**";              // mysql user 입력
char password[] = "***";        // mysql password 입력
 
// Sample query

EthernetClient client;
MySQL_Connection conn((Client *)&client);


 
void setup() {
  Serial.begin(9600);
  while (!Serial); // wait for serial port to connect
  Ethernet.begin(mac_addr);
  Serial.println("Connecting...");
  if (conn.connect(server_addr, 3306, user, password)) {
    delay(1000);
  }
  else
    Serial.println("Connection failed.");
}
 
 
void loop() {
  delay(2000);
  
int SensorReading1 = analogRead(SensorPin1);
int SensorReading2 = analogRead(SensorPin2);
int SensorReading3 = analogRead(SensorPin3);

int mfsr_r18 = map(SensorReading1, 0, 1024, 0, 255);
if ( mfsr_r18 >= 1 ) 
{
     const PROGMEM char UPDATE_SQL[] =  "UPDATE userdb.ParkingLotSpace set is_park='1' where P_number = 'park101' and Reserv != '1'" ;
     Serial.println("Recording data.");
     
     
  MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);
  cur_mem->execute(UPDATE_SQL);
 
  delete cur_mem;
}
else 
{
   const PROGMEM char UPDATE_SQL[] = "UPDATE userdb.ParkingLotSpace set is_park='0' where P_number = 'park101'and Reserv != '1'";
Serial.println("Recording data.");
 
  MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);

  cur_mem->execute(UPDATE_SQL);
  delete cur_mem;

}


int mfsr_r19 = map(SensorReading2, 0, 1024, 0, 255);
if ( mfsr_r19 >= 1 ) 
{
    const PROGMEM char UPDATE_SQL[] = "UPDATE userdb.ParkingLotSpace set is_park='1' where P_number = 'park102'and Reserv != '1'";

 Serial.println("Recording data.");
  MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);

  cur_mem->execute(UPDATE_SQL);

  delete cur_mem;
} 
else 
{
   const PROGMEM char UPDATE_SQL[] = "UPDATE userdb.ParkingLotSpace set is_park='0' where P_number = 'park102'and Reserv != '1'";

 Serial.println("Recording data.");
  MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);

  cur_mem->execute(UPDATE_SQL);

  delete cur_mem;
}

int mfsr_r20 = map(SensorReading3, 0, 1024, 0, 255);
if ( mfsr_r20 >= 1 ) 
{
    const PROGMEM char UPDATE_SQL[] = "UPDATE userdb.ParkingLotSpace set is_park='1' where P_number = 'park103'and Reserv != '1'";

 Serial.println("Recording data.");
  MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);

  cur_mem->execute(UPDATE_SQL);

  delete cur_mem;
} 
else 
{
   const PROGMEM char UPDATE_SQL[] = "UPDATE userdb.ParkingLotSpace set is_park='0' where P_number = 'park103'and Reserv != '1'";

 Serial.println("Recording data.");
  MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);

  cur_mem->execute(UPDATE_SQL);

  delete cur_mem;
}

Serial.println(mfsr_r18);
Serial.println(mfsr_r19);
Serial.println(mfsr_r20);

}

table
table868×276 12.6 KB

I want to store the parkempty value of park1 in the variable 'A' in Arduino, what should I do?

2

Have you seen the example sketches?

3

yes
I saw it, but I want to take out the data I want, but it's not working well.I'm sorry.

4

Can you post what you tried?

5

If the IS_PARK value of the table is 1, the data is taken from the table, and the condition statement is attached to Arduino, and the EMPTY value is -1.

6

I find ESP32 HTTP GET and HTTP POST with Arduino IDE | Random Nerd Tutorials does a good job of putting and getting data from my web sites db.

7

Do you know how SQL queries work?

8

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