Go: go-sql-driver/mysql (MySQL)

Connects, creates a todo table if it does not exist, inserts a row and counts open rows. The code is the same against the original database and against MachSQL; only the address changes.

The only change

MYSQL_DSN="app:${DB_PASSWORD}@tcp(old-mysql:3306)/app"
MYSQL_DSN="app:${DB_PASSWORD}@tcp(machsql-host:3306)/app"

Nothing else changes: not the code, not the driver, not its version, not the SQL.

Versions

• Go 1.27
• go-sql-driver/mysql v1.10.1

Run

go mod tidy
export MYSQL_DSN="app:${DB_PASSWORD}@tcp(machsql-host:3306)/app"
go run .

Expected output: inserted todo <id>, <n> open.

Source

The program as it is kept and tested in the Mach Database for PostgreSQL repository; highlighted lines read the connection setting.

main.go

// database/sql with go-sql-driver/mysql.
package main

import (
  "database/sql"
  "fmt"
  "os"

  _ "github.com/go-sql-driver/mysql"
)

func main() {
  db, err := sql.Open("mysql", os.Getenv("MYSQL_DSN"))
  if err != nil {
    fail(err)
  }
  defer db.Close()

  if _, err := db.Exec("CREATE TABLE IF NOT EXISTS todo (id BIGINT AUTO_INCREMENT PRIMARY KEY, title VARCHAR(200) NOT NULL, done BOOLEAN NOT NULL DEFAULT FALSE)"); err != nil {
    fail(err)
  }
  res, err := db.Exec("INSERT INTO todo (title) VALUES (?)", "write the examples")
  if err != nil {
    fail(err)
  }
  id, err := res.LastInsertId()
  if err != nil {
    fail(err)
  }
  var open int64
  if err := db.QueryRow("SELECT count(*) FROM todo WHERE NOT done").Scan(&open); err != nil {
    fail(err)
  }
  fmt.Printf("inserted todo %d, %d open\n", id, open)
}

func fail(err error) {
  fmt.Fprintln(os.Stderr, err)
  os.Exit(1)
}

go.mod

module example.com/machsql/go-mysql

go 1.27

require github.com/go-sql-driver/mysql v1.10.1