如何在Golang中从DAO函数返回mysql查询错误

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

func GetUserData() ([]User, error) {
    db, err := sql.Open("mysql", "user:password@tcp(host:port)/database")
    if err != nil {
        return nil, fmt.Errorf("failed to open database connection: %v", err)
    }
    defer db.Close()

    // 执行查询操作
    rows, err := db.Query("SELECT * FROM users")
    if err != nil {
        return nil, fmt.Errorf("failed to execute query: %v", err)
    }
    defer rows.Close()

    // 处理查询结果
    var users []User
    for rows.Next() {
        var user User
        err := rows.Scan(&user.ID, &user.Name, &user.Email)
        if err != nil {
            return nil, fmt.Errorf("failed to scan row: %v", err)
        }
        users = append(users, user)
    }
    if err := rows.Err(); err != nil {
        return nil, fmt.Errorf("failed to iterate over rows: %v", err)
    }

    return users, nil
}

users, err := GetUserData()
if err != nil {
    // 处理错误
    fmt.Printf("failed to get user data: %v", err)
    return
}

// 处理查询结果
for _, user := range users {
    fmt.Printf("User ID: %d, Name: %s, Email: %s\n", user.ID, user.Name, user.Email)
}