I am trying to connect the MySql DB using Go Language and gives me following error.
sql: unknown driver "mysql" (forgotten import?)
My Code
package main
import (
"database/sql"
"fmt"
)
func main() {
db, err := sql.Open("mysql", "astaxie:astaxie@/test?charset=utf8")
checkErr(err);
err=db.Ping();
}
Also when I import
_ "github.com/go-sql-driver/mysql"
I am getting error of
imported and not used
For others coming to this page as a result of the error sql: unknown driver "mysql" (forgotten import?), the database/sql package must be used in conjunction with a database driver. That means in addition to importing the database/sql package, you need to import a database driver.
For example, for mysql, you could use the package go-sql-driver. Typically, you import this package using the underscore _ notation, meaning it is imported for its side effects only:
import _ "github.com/go-sql-driver/mysql"
You can read more about this and find a list of SQL drivers below:
database/sql does not provide an implementation for specific sql databases, only a generic interface -- the driver implements the logic that interfaces with the specific database, in this case mysql (handling connections to the database, executing queries, preparing statements, etc)Try it again, but look for my NOTEs:
package main
import (
"database/sql"
_ "github.com/go-sql-driver/mysql"
)
// NOTE - I removed the import for "fmt" because it was unused.
func main() {
db, err := sql.Open("mysql", "astaxie:astaxie@/test?charset=utf8")
checkErr(err);
err=db.Ping();
// NOTE - the above line will trigger an error because err is unused.
}
I added the import for the MySQL driver and removed "fmt" because it was unused. This may be the cause of your "imported and not used" error.
Try to recheck the location of the packages. I made such a mistake when I manually added this package to the project. It is best to clean GOROOT and GOPATH from this package and reinstall/reconnect it as indicated in the source: https://github.com/go-sql-driver/mysql
A more modern implementation shouldn't need to use unused imports like the other answers have been suggesting. According to https://cloud.google.com/sql/docs/mysql/connect-app-engine-standard#go_1, you should be using something like this:
import (
"cloud.google.com/go/cloudsqlconn"
"github.com/go-sql-driver/mysql"
)
func connectWithConnector() (*sql.DB, error) {
d, err := cloudsqlconn.NewDialer(context.Background(), cloudsqlconn.WithLazyRefresh())
if err != nil {
return nil, fmt.Errorf("cloudsqlconn.NewDialer: %w", err)
}
var opts []cloudsqlconn.DialOption
if env.usePrivate != "" {
opts = append(opts, cloudsqlconn.WithPrivateIP())
}
mysql.RegisterDialContext("cloudsqlconn",
func(ctx context.Context, addr string) (net.Conn, error) {
return d.Dial(ctx, env.instanceConnectionName, opts...)
})
dbPool, err := sql.Open("mysql", dbConnString)
if err != nil {
return nil, fmt.Errorf("sql.Open: %w", err)
}
return dbPool, nil
}
Make sure that your network name (in the connection string) matches the one passed to mysql.RegisterDialContext. Additionally, your instance name should be the one listed on https://console.cloud.google.com/sql (of the form project:region:instance-id).
_ "github.com/go-sql-driver/mysql"? It shouldn't give imported and not used when you put underscore before package name.