MySQL is a widely used relational database management system (RDBMS) that uses structured query language (SQL). At some point, you may want to upload Arduino/NodeMCU sensor data to the MySQL database. In this Instructable, we will see how to connect NodeMCU ESP8266 to the MySQL database.

Here I am going to use 000webhost to host MySQL database because of simplicity and free availability. However, you can use any platform with LAMP (Linux, Apache, MySQL/MariaDB, PHP) stack installed on it. Even you can use XAMPP to host MySQL database locally on your Windows PC.

In this instructable, I am not going to use any sensor. I will just increment two variables and insert them into the database. However, you can connect any sensor with your board.

Requirements:-

NodeMCU ESP8266 development board
Free version of 000webhost account (or MySQL installed on localhost)
Filezilla FTP client (free version)

Step 1: Create Web Application

Navigate to 000webhost.com and login to your account.
Locate Create New Site button on the top right corner of the window.
Enter desired site name and password and then hit the create button. (Note down site password in a safe place because we are going to use it in upcoming steps).
Proceed to Manage Website option.

Step 2: Create MySQL Database

Navigate to Tools >> Database Manager and then create a new database.

After successfully creating the database, proceed to Manage >> PhpMyAdmin.

Step 3: Create MySQL Database Table

Locate and click on the database name in the left panel of PhpMyAdmin Window (as shown in screenshot a).
Enter table name and number of columns (let it be 5). Then hit the Go button.
Create columns (as per schema shown in screenshot b) and then hit save button.

Alternatively, you can create table by running the below command:-

CREATE TABLE `id13263538_sumodb`.`nodemcu_table` ( `id` INT(10) NOT NULL AUTO_INCREMENT , `val` FLOAT(10) NOT NULL , `val2` FLOAT(10) NOT NULL , `date` DATE NOT NULL , `time` TIME NOT NULL , PRIMARY KEY (`id`)) ENGINE = InnoDB;

Step 4: Download and Edit PHP Files

Download dbwrite.php and dbread.php file from Github (or download attached files).
Update database details and table name in dbwrite.php and dbread.php (as shown in screenshot).

Step 5: Upload PHP Files to the Server

Navigate to Manage Website >> Website Settings >> General.
Note down hostname, username, port and password (password is same as site password created in step1).
Use these details to connect to the server using Filezilla FTP client (as shown in screenshot).
Navigate to public_html folder and upload dbwrite.php and dbread.php files.

Step 6: Edit and Upload Arduino (.ino) File to NodeMCU ESP8266

Navigate to Manage Website >> Website Settings >> General and note down Website_Name (site URL).
Edit .ino file to replace example.com with the name of your site. Also don't forget to update WiFi SSID and password.
Finally, Upload code to NodeMCU.