Arduino ESP8266 WiFi MySQL database connection with INSERT SQL command

PlantMoistureSensor.ino

//#include <DHT.h>
#include <MySQL_Connection.h>
#include <MySQL_Cursor.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>

#define sensorPin1 0

//#define sensorPin2 D2
//#define typeDHT DHT11
//DHT dht(sensorPin1, typeDHT);

char ssid[] = "xxx";                 // Network Name
char pass[] = "xxx";                 // Network Password
byte mac[6];

WiFiServer server(80);
IPAddress ip(192, 168, x, x);
IPAddress gateway(192, 168, x, x);
IPAddress subnet(255, 255, 255, 0);

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

char INSERT_SQL[] = "INSERT INTO officeto_plants.TBL_READINGS(ID_PLANT, AIR_HUMIDITY, AIR_TEMPERATURE, SOIL_MOISTURE_1) VALUES (1, NULL, NULL, %d)";
//char INSERT_SQL[] = "INSERT INTO officeto_plants.TBL_READINGS(ID_PLANT, AIR_HUMIDITY, AIR_TEMPERATURE, SOIL_MOISTURE_1, SOIL_MOISTURE_2) VALUES (1, NULL, NULL, %d, %d)";
char query[128];

IPAddress server_addr(x, x ,x, x);          // MySQL server IP
char user[] = "xxx";           // MySQL user
char password[] = "xxx";       // MySQL password

void setup() {

  Serial.begin(9600);

  pinMode(sensorPin1, INPUT);
  //pinMode(sensorPin2, INPUT);

  Serial.println("Initialising connection");
  Serial.print(F("Setting static ip to : "));
  Serial.println(ip);

  Serial.println("");
  Serial.println("");
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.config(ip, gateway, subnet); 
  WiFi.begin(ssid, pass);

  while (WiFi.status() != WL_CONNECTED) {
    delay(200);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi Connected");

  WiFi.macAddress(mac);
  Serial.print("MAC: ");
  Serial.print(mac[5],HEX);
  Serial.print(":");
  Serial.print(mac[4],HEX);
  Serial.print(":");
  Serial.print(mac[3],HEX);
  Serial.print(":");
  Serial.print(mac[2],HEX);
  Serial.print(":");
  Serial.print(mac[1],HEX);
  Serial.print(":");
  Serial.println(mac[0],HEX);
  Serial.println("");
  Serial.print("Assigned IP: ");
  Serial.print(WiFi.localIP());
  Serial.println("");

  Serial.println("Connecting to database");

  while (conn.connect(server_addr, 3306, user, password) != true) {
    delay(200);
    Serial.print ( "." );
  }

  Serial.println("");
  Serial.println("Connected to SQL Server!");  

}

void loop() {

  int soil_hum = 1024 - analogRead(sensorPin1);
  //float t = dht.readTemperature();

  //Serial.println(t);

  delay(10000); //10 sec

  sprintf(query, INSERT_SQL, soil_hum);
  //sprintf(query, INSERT_SQL, soil_hum, t);

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

  delete cur_mem;

}

It´s really works?

I have not to this ESP8266 works directly with my data base MYSQ...

Where are the problem?

It works with Wemos D1 R2 boards.
Check IP settings and database details. MySQL is also case sesitive so this must be reflecred in the code.

How can select the db???
I try with the sample and have the next error:

Connected to server version 5.5.46

Connected to SQL Server!
Recording data.
SELECT * FROM DATOS
Error: 29 = No database selected.

Hi, thank you for sharing the code. I've been trying to implement it with a Wemos NodeMCU V3.

So far the board is connecting to the WIFI network but isn't able to connect to the SQL Server, it just keeps printing dots in the Serial Monitor. Does it have to be a local Server? I'm using an external host, which IP I got using a 3rd party online tool because I only had the Hostname. Is it possible that I'm writing the wrong IP?

I saw an example of the MYSQL_Connection library that uses the Hostname instead of the IP, however it is written for Ethernet connection and I'm not really sure how to make it work with esp8266's WIFI. Here is what I've tried, but it doesn't compile:

`#include <MySQL_Connection.h>
#include <MySQL_Cursor.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <Dns.h> //EDIT

#define sensorPin1 0

//#define sensorPin2 D2
//#define typeDHT DHT11
//DHT dht(sensorPin1, typeDHT);

char ssid[] = "-----"; // Network Name
char pass[] = "-----"; // Network Password
byte mac[6];

WiFiServer server(80);
IPAddress ip(192, 168, x, x);
IPAddress gateway(192, 168, x, x);
IPAddress subnet(255, 255, 255, 0);

WiFiClient client;
MySQL_Connection conn((Client *)&client);
DNSClient dns_client; //EDIT

char INSERT_SQL[] = "INSERT INTO officeto_plants.TBL_READINGS(ID_PLANT, AIR_HUMIDITY, AIR_TEMPERATURE, SOIL_MOISTURE_1) VALUES (1, NULL, NULL, %d)";
//char INSERT_SQL[] = "INSERT INTO officeto_plants.TBL_READINGS(ID_PLANT, AIR_HUMIDITY, AIR_TEMPERATURE, SOIL_MOISTURE_1, SOIL_MOISTURE_2) VALUES (1, NULL, NULL, %d, %d)";
char query[128];

//EDIT
IPAddress server_addr;

//char hostname[] = "hostname";
//IPAddress server_addr(x,x, x, x); // MySQL server IP
char user[] = "----"; // MySQL user
char password[] = "----"; // MySQL password
//End EDIT

void setup() {

Serial.begin(9600);

Serial.println("Initialising connection");
Serial.print(F("Setting static ip to : "));
Serial.println(ip);

Serial.println("");
Serial.println("");
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.config(ip, gateway, subnet);
WiFi.begin(ssid, pass);

while (WiFi.status() != WL_CONNECTED) {
delay(200);
Serial.print(".");
}

Serial.println("");
Serial.println("WiFi Connected");

WiFi.macAddress(mac);
Serial.print("MAC: ");
Serial.print(mac[5],HEX);
Serial.print(":");
Serial.print(mac[4],HEX);
Serial.print(":");
Serial.print(mac[3],HEX);
Serial.print(":");
Serial.print(mac[2],HEX);
Serial.print(":");
Serial.print(mac[1],HEX);
Serial.print(":");
Serial.println(mac[0],HEX);
Serial.println("");
Serial.print("Assigned IP: ");
Serial.print(WiFi.localIP());
Serial.println("");

Serial.println("Connecting to database");

// EDIT
dns_client.begin(Ethernet.dnsServerIP());
dns_client.getHostByName(hostname, server_addr);
Serial.println(server_addr);
// End EDIT

while (conn.connect(server_addr, 3306, user, password) != true) {
delay(200);
Serial.print ( "." );
}

Serial.println("");
Serial.println("Connected to SQL Server!");

}`

Thank you in advance.

simplest way to select database : select * from dbname.tablename

example: "INSERT INTO mydatabase.temp_log (Location,temperature,humidity) VALUES (1,2,3)";

Hi I read your code and thanks to upload your code.
I want to insert data to mysql that is made on Linux(Raspberry pi)
If I use this code I can insert data from arduino to mysql except coding in Linux?

Hi, can I use this code to send data to MS SQL server instead of mysql ?

i'll try it. thanks for sharing.

how do i use the code to upload it on arduino uno rather than esp8266 directly. because this is only a part of the code and the rest of it needs arduino as the main processor. When I try to upload the code onto a arduino uno it shows that esp8266wifi.h file is missing. any suggestions will be appericiated.
and thanks in advance
this is my code

#include <ESP8266WiFi.h>
#include <MySQL_Connection.h>
#include <MySQL_Cursor.h>
#include <WiFiClient.h>
#include <SPI.h>
#include <MFRC522.h>
#include <SoftwareSerial.h>

//pin connecction configuration
#define rxPin 2 // Serial input (connects to Emic 2 SOUT)
#define txPin 3 // Serial output (connects to Emic 2 SIN)
#define SS_PIN 10
#define RST_PIN 9
#define RX 5
#define TX 6
SoftwareSerial esp8266(RX,TX);
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
SoftwareSerial emicSerial = SoftwareSerial(rxPin, txPin);

char ssid[] = "Airtel-WD670-71CE";// Network Name
char pass[] = "D8F171CE"; // Network Password
byte mac[6];

WiFiServer server(80);
IPAddress ip(192, 168, 1, 100);//192.168.1.100
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 255, 0);

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

IPAddress server_addr(104,20 ,67,46); // MySQL server IP
char user[] = "id4857053_nithish"; // MySQL user
char password[] = "arjun4694"; // MySQL password

//query instruction
const char QUERY_POP[] = "SELECT name,cost,description FROM id4857053_database.details WHERE id='content';";
char query[128];

void setup() {

//setup of mfrc522
Serial.begin(9600); // Initiate a serial communication
SPI.begin(); // Initiate SPI bus
mfrc522.PCD_Init(); // Initiate MFRC522
Serial.println("Approximate your card to the reader...");
Serial.println();

esp8266.begin(115200);

//emic2 pinout details
pinMode(rxPin, INPUT);
pinMode(txPin, OUTPUT);

// set the data rate for the SoftwareSerial port
emicSerial.begin(9600);
emicSerial.print('\n'); // Send a CR in case the system is already up
while (emicSerial.read() != ':'); // When the Emic 2 has initialized and is ready, it will send a single ':' character, so wait here until we receive it
delay(10); // Short delay
emicSerial.flush(); // Flush the receive buffer

//setting up esp8266 connection
Serial.println("Initialising connection");
Serial.print(F("Setting static ip to : "));
Serial.println(ip);

Serial.println("");
Serial.println("");
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.config(ip, gateway, subnet);
WiFi.begin(ssid, pass);

while (WiFi.status() != WL_CONNECTED) {
delay(200);
Serial.print(".");
}

Serial.println("");
Serial.println("WiFi Connected");

WiFi.macAddress(mac);
Serial.print("MAC: ");
Serial.print(mac[5],HEX);
Serial.print(":");
Serial.print(mac[4],HEX);
Serial.print(":");
Serial.print(mac[3],HEX);
Serial.print(":");
Serial.print(mac[2],HEX);
Serial.print(":");
Serial.print(mac[1],HEX);
Serial.print(":");
Serial.println(mac[0],HEX);
Serial.println("");
Serial.print("Assigned IP: ");
Serial.print(WiFi.localIP());
Serial.println("");

Serial.println("Connecting to database");

while (conn.connect(server_addr, 3306, user, password) != true) {
delay(200);
Serial.print ( "." );
}

Serial.println("");
Serial.println("Connected to SQL Server!");

}

void loop() {

// Look for new cards
if ( ! mfrc522.PICC_IsNewCardPresent())
{
return;
}
// Select one of the cards
if ( ! mfrc522.PICC_ReadCardSerial())
{
return;
}
//Show UID on serial monitor
Serial.print("UID tag :");
String content= "";
byte letter;
for (byte i = 0; i < mfrc522.uid.size; i++)
{
Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
Serial.print(mfrc522.uid.uidByte[i], HEX);
content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));
content.concat(String(mfrc522.uid.uidByte[i], HEX));
}
Serial.println();
Serial.print("Message : ");
content.toUpperCase();

delay(10000); //10 sec

Serial.println("> Running SELECT with dynamically supplied parameter");

// Initiate the query class instance
MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);
// Supply the parameter for the query
// Here we use the QUERY_POP as the format string and query as the
// destination. This uses twice the memory so another option would be
// to allocate one buffer for all formatted queries or allocate the
// memory as needed (just make sure you allocate enough memory and
// free it when you're done!).
sprintf(query, QUERY_POP, 9000000);
// Execute the query
cur_mem->execute(query);
// Fetch the columns and print them
column_names *cols = cur_mem->get_columns();
for (int f = 0; f < cols->num_fields; f++) {
Serial.print(cols->fields[f]->name);
emicSerial.print('S');
emicSerial.print(cols->fields[f]->name);
emicSerial.print('\n');
while (emicSerial.read() != ':'); // Wait here until the Emic 2 responds with a ":" indicating it's ready to accept the next command
delay(500);
if (f < cols->num_fields-1) {
Serial.print(',');
}
}
Serial.println();
// Read the rows and print them
row_values *row = NULL;
do {
row = cur_mem->get_next_row();
if (row != NULL) {
for (int f = 0; f < cols->num_fields; f++) {
Serial.print(row->values[f]);
emicSerial.print(row->values[f]);
emicSerial.print('S');
emicSerial.print(cols->fields[f]->name);
emicSerial.print('\n');
while (emicSerial.read() != ':'); // Wait here until the Emic 2 responds with a ":" indicating it's ready to accept the next command
delay(500);
if (f < cols->num_fields-1) {
Serial.print(',');
}
}
Serial.println();
}
} while (row != NULL);
// Deleting the cursor also frees up memory used
delete cur_mem;

}

Hey,

how can I read Data from the table? And save it to strings or ints?

Thanks Timo

the program does not want to connect to my SQL database.
I have a maria DB on my synology NAS.
Can someone help me?

I tried to connect ESP8266 with MySQL DB. Done multiple attempts in last 7 days, BUT NO LUCK. Can someone help me please?

Please do reply on email - prasadgiot@gmail.com

Great post
Have a question...
How is password to MySQL sent?
Clear text or ?
Might be a stupid question, but just want to be sure.

hai, iam working on nodeMCU ,i want to send the url to the mysql database using apache tomcat webserver. using below code i sent to the server but it's not send.plaese help me.

code
#include <ESP8266HTTPClient.h>
#include <ESP8266WiFi.h>

void setup() {

Serial.begin(115200); //Serial connection
WiFi.begin("iota_telecom", "iota160616"); //WiFi connection

while (WiFi.status() != WL_CONNECTED) { //Wait for the WiFI connection completion

delay(500);
Serial.println("Waiting for connection");

}

}

void loop() {

if(WiFi.status()== WL_CONNECTED){ //Check WiFi connection status

HTTPClient http; //Declare object of class HTTPClient

http.begin("http://10.132.16.241:8080/HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45"); //Specify request destination
http.addHeader("Content-Type", "text/plain"); //Specify content-type header

int httpCode = http.POST("http://10.132.16.241:8080/HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45"); //Send the request
String payload = http.getString(); //Get the response payload

Serial.println(httpCode); //Print HTTP return code
Serial.println(payload); //Print request response payload

http.end(); //Close connection

}else{

Serial.println("Error in WiFi connection");   

}

delay(30000); //Send a request every 30 seconds

}

serial monitor:

Waiting for connection
state: 2 -> 0 (2)
reconnect
scandone
state: 0 -> 2 (b0)
Waiting for connection
state: 2 -> 3 (0)
state: 3 -> 5 (10)
add 0
aid 2
cnt
Waiting for connection
Waiting for connection
Waiting for connection

connected with iota_telecom, channel 6
dhcp client start...
Waiting for connection
ip:10.132.39.81,mask:255.255.0.0,gw:10.132.0.1
Waiting for connection
[HTTP-Client][begin] url: http://10.132.16.241:8080/HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45
[HTTP-Client][begin] host: 10.132.16.241 port: 8080 url: /HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45
[HTTP-Client] connected to 10.132.16.241:8080
[HTTP-Client] sending request header

POST /HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45 HTTP/1.1
Host: 10.132.16.241:8080
User-Agent: ESP8266HTTPClient
Connection: close
Accept-Encoding: identity;q=1,chunked;q=0.1,*;q=0
Content-Type: text/plain
Content-Length: 136

---

[HTTP-Client][returnError] error(-11): read Timeout
[HTTP-Client][returnError] tcp stop
[HTTP-Client][returnError] error(-4): not connected
-11

[HTTP-Client][end] tcp is closed
[HTTP-Client][begin] url: http://10.132.16.241:8080/HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45
[HTTP-Client][begin] host: 10.132.16.241 port: 8080 url: /HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45
[HTTP-Client] failed connect to 10.132.16.241:8080
[HTTP-Client][returnError] error(-1): connection refused
[HTTP-Client][returnError] error(-4): not connected
-1

[HTTP-Client][end] tcp is closed
[HTTP-Client][begin] url: http://10.132.16.241:8080/HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45
[HTTP-Client][begin] host: 10.132.16.241 port: 8080 url: /HTTPHITURL/RequestHandler?p1=300&p2=78&p3=500&p4=600&p5=500&p6=iota66&p7=iota77&p8=iota83&p9=iota84&p10=iota45
[HTTP-Client] failed connect to 10.132.16.241:8080
[HTTP-Client][returnError] error(-1): connection refused
[HTTP-Client][returnError] error(-4): not connected
-1
thank you

Hi, i use that code to trying connect my ESP8266 to my SQL Server, but till now, i'm still failed to connect it, do you have any idea about what happen, this is my code..
`#include <ESP8266WiFi.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <WiFiClient.h>
#include <MySQL_Connection.h>
#include <MySQL_Cursor.h>
#include <ESP8266Ping.h>

//--------------------------------------------------------
//DS18B20
#define ONE_WIRE_BUS 2
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature DS18B20(&oneWire);
long lastTime;
const int durationTemp = 1000; //The frequency of temperature measurement

//--------------------------------------------------------
//WIFI
const char* ssid = "xxx"; //type your ssid
const char* password = "xxxXXX"; //type your password

WiFiServer server(80);
WiFiClient client;

//--------------------------------------------------------
//SQL
MySQL_Connection conn((Client *)&client);
char INSERT_SQL[] = "INSERT INTO db_test.table_temp(ID, TIME, TEMP) VALUES (1, NULL, %f)";
char query[128];
IPAddress server_addr(192, 168, 43, 66); //MySQL server IP (I USE LAPTOP AS SERVER)
char sqlUser[] = "xxx"; //MySQL user
char sqlPassword[] = "xxxXXX"; //MySQL password

//--------------------------------------------------------
//Setting The Temperature Sensor
void SetupDS18B20(){
DS18B20.begin();
Serial.print("Parasite power is: ");
if(DS18B20.isParasitePowerMode()){
Serial.print("On");
}
else{
Serial.print("Off");
}

lastTime = millis();
DS18B20.requestTemperatures();
}

//--------------------------------------------------------
void setup() {
Serial.begin(115200);

Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);

Serial.println("Set to STA mode");
WiFi.mode(WIFI_STA);

WiFi.begin(ssid, password);

while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}

Serial.println("");
Serial.print("Connected to ");
Serial.println(ssid);
Serial.print("IP address: ");
Serial.println(WiFi.localIP());

// Start the server
server.begin();
Serial.println("Server started");

SetupDS18B20();

IPAddress pingt (192, 168, 43, 66); // The remote ip to ping
bool ret = Ping.ping(pingt);

Serial.println("");
Serial.print("SQL Server is ");
if(ret){
Serial.print("Reachable");
}
else{
Serial.print("Unreachable");
}

Serial.println("");
Serial.println("Connecting to database");

while (conn.connect(server_addr, 3306, sqlUser, sqlPassword) != true) {
delay(200);
Serial.print ( "." );
}

Serial.println("");
Serial.println("Connected to SQL Server!");
}`

It fail to connect SQL Server. my ESP also have same network as my laptop (as server). Do you happen know whats wrong.. thanks..

Guys, if you have access to a server, it's better to use a MQTT broker, and then use a local app to manage the connection between the db and MQTT

Hi guys,
how does one redefine the sql credentials? I have them stored in EEPROM i can load them, but they are not global, so the function that uses it restarts the ESP8266 module.

Oh yes, to the connection problem. Had the same issue: permission. Could not access MariaDB on my RasPi server, had to add a user with permissions to mysql>user with % as host... Did that via phpMyAdmin, work like a charm now.

Could anyone explain these queries?

1. char INSERT_SQL[] = "INSERT INTO officeto_plants.TBL_READINGS(ID_PLANT, AIR_HUMIDITY, AIR_TEMPERATURE, SOIL_MOISTURE_1) VALUES (1, NULL, NULL, %d)";

2. sprintf(query, INSERT_SQL, soil_hum);

@jasontechie

1. it's the sql command the %d is the soil_hum in the sprintf
2. sprintf add all of these values to one

can u explain line 25 for me, Sir..
i didnt understand cause i not see ur database.

The above code was working with MySQL databases.
I still recommend using ESP8266WebServer. MySQL library used in this project was not reliable.
It consumes too much memory and the program crashed very often.

And as some people mentioned, the connection issues may be caused by your server as well.
I had to grant permission to arduino IP so that i could insert the records.

Someone asked about selects. The are some sample sketched attached to MySQL library but I did not try them.

thanks for sharing

Thanks a lot bro ..
Make sure while entering the database parameters .....

Nice! - Thank you, works very well.

Hi, thank you for sharing the code. I've been trying to implement it with a Wemos NodeMCU V3.

So far the board is connecting to the WIFI network but isn't able to connect to the SQL Server, it just keeps printing dots in the Serial Monitor. Does it have to be a local Server? I'm using an external host, which IP I got using a 3rd party online tool because I only had the Hostname. Is it possible that I'm writing the wrong IP?

I saw an example of the MYSQL_Connection library that uses the Hostname instead of the IP, however it is written for Ethernet connection and I'm not really sure how to make it work with esp8266's WIFI. Here is what I've tried, but it doesn't compile:

`#include <MySQL_Connection.h>
#include <MySQL_Cursor.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <Dns.h> //EDIT

#define sensorPin1 0

//#define sensorPin2 D2
//#define typeDHT DHT11
//DHT dht(sensorPin1, typeDHT);

char ssid[] = "-----"; // Network Name
char pass[] = "-----"; // Network Password
byte mac[6];

WiFiServer server(80);
IPAddress ip(192, 168, x, x);
IPAddress gateway(192, 168, x, x);
IPAddress subnet(255, 255, 255, 0);

WiFiClient client;
MySQL_Connection conn((Client *)&client);
DNSClient dns_client; //EDIT

char INSERT_SQL[] = "INSERT INTO officeto_plants.TBL_READINGS(ID_PLANT, AIR_HUMIDITY, AIR_TEMPERATURE, SOIL_MOISTURE_1) VALUES (1, NULL, NULL, %d)";
//char INSERT_SQL[] = "INSERT INTO officeto_plants.TBL_READINGS(ID_PLANT, AIR_HUMIDITY, AIR_TEMPERATURE, SOIL_MOISTURE_1, SOIL_MOISTURE_2) VALUES (1, NULL, NULL, %d, %d)";
char query[128];

//EDIT
IPAddress server_addr;

//char hostname[] = "hostname";
//IPAddress server_addr(x,x, x, x); // MySQL server IP
char user[] = "----"; // MySQL user
char password[] = "----"; // MySQL password
//End EDIT

void setup() {

Serial.begin(9600);

Serial.println("Initialising connection");
Serial.print(F("Setting static ip to : "));
Serial.println(ip);

Serial.println("");
Serial.println("");
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.config(ip, gateway, subnet);
WiFi.begin(ssid, pass);

while (WiFi.status() != WL_CONNECTED) {
delay(200);
Serial.print(".");
}

Serial.println("");
Serial.println("WiFi Connected");

WiFi.macAddress(mac);
Serial.print("MAC: ");
Serial.print(mac[5],HEX);
Serial.print(":");
Serial.print(mac[4],HEX);
Serial.print(":");
Serial.print(mac[3],HEX);
Serial.print(":");
Serial.print(mac[2],HEX);
Serial.print(":");
Serial.print(mac[1],HEX);
Serial.print(":");
Serial.println(mac[0],HEX);
Serial.println("");
Serial.print("Assigned IP: ");
Serial.print(WiFi.localIP());
Serial.println("");

Serial.println("Connecting to database");

// EDIT
dns_client.begin(Ethernet.dnsServerIP());
dns_client.getHostByName(hostname, server_addr);
Serial.println(server_addr);
// End EDIT

while (conn.connect(server_addr, 3306, user, password) != true) {
delay(200);
Serial.print ( "." );
}

Serial.println("");
Serial.println("Connected to SQL Server!");

}`

Thank you in advance.

Hi @DaniNedo , did you find a way to do that?

First Point Connecting to WiFi Network doesn't mean you have internet connection; Once check the internet through the WiFi you have connected.
Second It need not be a local server; I had connected to a external host using a IP provided by the 3rd party;
Most probably your giving the wrong IP.

I'm getting this error

Exception (28):
epc1=0x402017d0 epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000049 depc=0x00000000

It works with Wemos D1 R2 boards.
Check IP settings and database details. MySQL is also case sesitive so this must be reflecred in the c

I'm getting this error on my Wemos D1 :

Exception (28):
epc1=0x4020152c epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000049 depc=0x00000000

stack>>>

ctx: cont
sp: 3ffffc10 end: 3fffffc0 offset: 0190
3ffffda0: 4000050c 2c9f0300 4000050c 3fffc278
3ffffdb0: 40102ce4 3fffc200 00000001 4020157f
3ffffdc0: 40227bf4 00000000 3ffe85c8 4020156c
3ffffdd0: 40203d8c 3fffefa0 00000000 402069cc
3ffffde0: fffffffc 00000000 00000000 fffffffe
3ffffdf0: ffffffff 3fffc6fc 0000005c 3ffee5b0
3ffffe00: 40206998 3ffe85c8 3ffee638 40203240
3ffffe10: 3ffef82c 3ffee638 00000000 40203264
3ffffe20: 3ffef82c 3ffee638 3ffee638 402032f4
3ffffe30: 3ffeeb48 00000000 00000000 4020198f
3ffffe40: 3ffffec0 40206e08 40100209 40215632
3ffffe50: 00000170 00000170 3ffe861c 401006c3
3ffffe60: 40202f34 3ffffebd 00000040 00000001
3ffffe70: 3ffefb9c 00000020 3ffefb9c 401008a2
3ffffe80: 007a1200 00000000 00000000 40100298
3ffffe90: 401059f5 001a24ca 3ffee828 40216098
3ffffea0: 00000102 00000102 3ffe861c 401006c3
3ffffeb0: 3ffe85c8 00000000 3ffef9c4 3ffe85c8
3ffffec0: 00000010 00000035 00000020 3ffe85c8
3ffffed0: 00000010 00000035 3ffee5b0 40201ad2
3ffffee0: 3ffef82c 00000050 3ffee5b0 40201842
3ffffef0: 0000004d 000003e8 3ffe8846 00000001
3fffff00: 3fffff60 00000000 3ffee5b0 40201382
3fffff10: 40206e60 73752ab9 3ffee738 40202f40
3fffff20: 00000cea ffffffff 00000001 3ffe85dd
3fffff30: 3ffe85c8 00000016 3ffee738 40203324
3fffff40: 3ffe889a 3ffee630 3ffee738 3ffe8846
3fffff50: 3ffe889a 3ffee630 3ffee738 40201224
3fffff60: 40206e60 73752ab9 40206e60 00000000
3fffff70: 40206e60 00ffffff 40206e60 0181a8c0
3fffff80: 40206e60 b181a8c0 feefeffe feefeffe
3fffff90: feefeffe feefeffe feefeffe 3ffee7c4
3fffffa0: 3fffdad0 00000000 3ffee7b0 40203eb0
3fffffb0: feefeffe feefeffe 3ffe8618 40100b55
<<<stack<<<