недопустимый символ в golang для подключения к mysql

Question

Я новичок, использую golang и пытаюсь подключиться к mySql

здесь мой исходный код. и когда я запустил этот пример кода, я получил ошибку. подробные сведения об ошибке приведены под исходным кодом

package main

import "database/sql"
import "fmt"
import _"github.com/go-sql-driver/mysql"

type trade_history struct {
        id, final_meta_report_id, trading_account_id, lp, lp2, lp3             int
        symbol, price, price_type, time, type, status, created_at, updated_at  string
        qty, pegged_distance, price_limit                                      double
}
var db *sql.DB
var err error

funct getTradingHistory (final_Meta_report_ID int) (err error){
        db, err = sql.Open("mysql", username:password@trade.asdewx134.us-east-2.rds.amazonaws.com:3306/trading_dashboard
        defer db.Close()
        if err != nil {
                fmt.Println(err.Error())
        }
        err = db.Ping()
        if err != nil{
        fmt.Println(err.Error())
        }
        var p trade_history
        err = db.QueryRow("select id, final_meta_report_id, trading_account_id, symbol, qty, price, price_type, time, lp, lp2, lp3, pegged_distance, price_limit, time_limit, type, status, created_at, u$
        if err !=nil {
        fmt.Println(err.Error())
        }
        fmt.Printf("id: %d\n Final_meta_report_id: %d\n trading_account_id: %d\n symbol: %s\n qty: %.2f\n price: %s\n price_type: %s\n time: %s\n lp: %d\n lp2: %d\n lp3: %d\n pegged_distance: %.2f\n pr$

        return err
}

func main(){
        getTradingHistory(2074)
}

Я получил такую ​​ошибку

# command-line-arguments
./myConnectionMySql.go:9:35: syntax error: unexpected type, expecting name
./myConnectionMySql.go:15:1: syntax error: non-declaration statement outside function body
./myConnectionMySql.go:16:56: invalid character U+0040 '@'
./myConnectionMySql.go:26:2: syntax error: non-declaration statement outside function body
./myConnectionMySql.go:30: newline in string

как исправить эту проблему?

Answer 1

Сделайте это так, коды имеют комментарии, вы можете прочитать их и адаптировать под свои нужды.

package main

import "database/sql"
import "fmt"
import _ "github.com/go-sql-driver/mysql"

type trade_history struct {
    // best practice in golang is to name your field in upper camel case if you intend to export it
    // or lower camel case if you don't.
    id, final_meta_report_id, trading_account_id, lp, lp2, lp3 int
    // `type` is reserved keyword, therefore for example, i use `ptype`
    symbol, price, price_type, time, ptype, status, created_at, updated_at string
    qty, pegged_distance, price_limit                                      double
}

// you don't need to declare global variable like this, if you want it to be accessible to all your packages
// it's best to use struct.
// var db *sql.DB
// var err error -- this one is shadowed by declaration of err in your getTradingHistory anyway.

func getTradingHistory(reportId int) (err error) {
    // Your dsn is unquoted hence error
    db, err := sql.Open("mysql", "username:password@trade.asdewx134.us-east-2.rds.amazonaws.com:3306/trading_dashboard")
    // your trade data is here

    defer db.Close()
    if err != nil {
        fmt.Println(err.Error())
    }
    err = db.Ping()
    if err != nil {
        fmt.Println(err.Error())
    }
    var th trade_history
    // this one is also unquoted and your SQL statement is not correct
    // here i add `FROM [YOUR TABLE] that you can edit to your needs`
    err = db.QueryRow("select id, final_meta_report_id, trading_account_id, symbol, qty, price, price_type, time, lp, lp2, lp3, pegged_distance, price_limit, time_limit, type, status, created_at FROM [YOUR TABLE] WHERE id = ?", reportId).Scan( /* Scan your fields here */ ) // This is where you should scan your fields.
    if err != nil {
        fmt.Println(err.Error())
    }
    fmt.Printf("id: %d\n Final_meta_report_id: %d\n trading_account_id: %d\n symbol: %s\n qty: %.2f\n price: %s\n price_type: %s\n time: %s\n lp: %d\n lp2: %d\n lp3: %d\n pegged_distance: %.2f\n pr$")
    return err
}

func main() {
    getTradingHistory(2074)
}

Answer 2

Вы должны исправить ошибки, посмотрите комментарии к коду, как показано ниже:

package main

import "database/sql"
import "fmt"
import _ "github.com/go-sql-driver/mysql"

type trade_history struct {
    id, final_meta_report_id, trading_account_id, lp, lp2, lp3 int
    symbol, price, price_type, time, typeField, status, created_at, updated_at string
    qty, pegged_distance, price_limit                                          double
}

var db *sql.DB

var err error


func getTradingHistory(final_Meta_report_ID int) (err error) {
    host := "trade.asdewx134.us-east-2.rds.amazonaws.com"
    port := 3306
    db := "trading_dashboard"

    //use Sprintf if you wanna parse a string with values
    conn := fmt.Sprintf("%s:%s@%s:%s/%s", username, password, host, port, db)
    db, err = sql.Open("mysql", conn)
    defer db.Close()
    if err != nil {
        fmt.Println(err.Error())
    }
    err = db.Ping()
    if err != nil {
        fmt.Println(err.Error())
    }
    var p trade_history

    //if you have multiple lines of texts use ` instead of "
    err = db.QueryRow(`select id, final_meta_report_id, 
    trading_account_id, symbol, qty, price, price_type, time, lp, 
    lp2, lp3, pegged_distance, price_limit, time_limit, type, status, created_at`).Scan(&p)
    if err != nil {
        fmt.Println(err.Error())
    }


    fmt.Printf("id: %d\n Final_meta_report_id: %d\n trading_account_id: %d\n symbol: %s\n qty: %.2f\n price: %s\n price_type: %s\n time: %s\n lp: %d\n lp2: %d\n lp3: %d\n pegged_distance: %.2f\n")

    return err
}

func main() {
    getTradingHistory(2074)
}