Connecting with Go

This guide explains how to establish a connection between a Go application and a MySQL database using the 
go-sql-driver/mysql package. It walks through the necessary setup, configuration, and execution of a simple SQL query.
Variables
Certain parameters must be provided to establish a successful connection to a MySQL database. Below is a breakdown of each required variable, its purpose, and where to find it. Here’s what each variable represents:
Variable
Description
Purpose
USER
MySQL username, from the Elestio service overview page
Identifies the database user who has permission to access the MySQL database.
PASSWORD
MySQL password, from the Elestio service overview page
The authentication key is required for the specified USER to access the database.
HOST
Hostname for MySQL connection, from the Elestio service overview page
The address of the server hosting the MySQL database.
PORT
Port for MySQL connection, from the Elestio service overview page
The network port used to connect to MySQL. The default port is 3306.
DATABASE
Database Name for MySQL connection, from the Elestio service overview page
The name of the database being accessed. A MySQL instance can contain multiple databases.
These values can usually be found in the Elestio service overview details, as shown in the image below. Make sure to take a copy of these details and add them to the code moving ahead.
Prerequisites
Install Go
Check if Go is installed by running: 
go version
If not installed, download it from golang.org and install.
Install the MySQL Driver
Use the following command to install the go-sql-driver/mysql driver: 
go get -u github.com/go-sql-driver/mysql
Code
Once all prerequisites are set up, create a new file named 
mysql_connect.go and add the following code:
package main
import (
	"database/sql"
	"fmt"
	"log"
	_ "github.com/go-sql-driver/mysql"
)
func main() {
	user := "USER"
	password := "PASSWORD"
	host := "HOST"
	port := "PORT"
	database := "DATABASE"
	// Construct DSN (Data Source Name)
	dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s", user, password, host, port, database)
	// Open a connection
	db, err := sql.Open("mysql", dsn)
	if err != nil {
		log.Fatalf("Connection failed: %v", err)
	}
	defer db.Close()
	// Ping to verify connection
	if err := db.Ping(); err != nil {
		log.Fatalf("Ping failed: %v", err)
	}
	fmt.Println("Connected to MySQL")
	// Run a test query to check the MySQL version
	var version string
	err = db.QueryRow("SELECT VERSION()").Scan(&version)
	if err != nil {
		log.Fatalf("Query execution failed: %v", err)
	}
	fmt.Printf("MySQL Version: %s\n", version)
}
To execute the script, open the terminal and navigate to the directory where 
mysql_connect.go is located. Once in the correct directory, run the script with the commands:
go mod init example.com/mysqlconnect
go run mysql_connect.go
If the connection is successful, the terminal will display output similar to:
Connected to MySQL
MySQL Version: 8.0.36