golang中用于连接mysql的无效字符

Question

我是使用 golang 的新手并尝试连接到 mySql这是我的源代码。当我运行这个示例代码时，我得到了错误。错误详细信息在源代码下方package mainimport "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.DBvar err errorfunct getTradingHistory (final_Meta_report_ID int) (err error){        db, err = sql.Open("mysql", username:[e-mail]: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)}我遇到了这样的错误# 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如何解决这个问题？

Answer 1

这样做，代码对它们有注释，您可以阅读并适应您的需求。

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:[e-mail]: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

您应该修复错误，查看代码注释如下：

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)

}