Markdium-

Markdium-Go.go

package main

import (
    "database/sql"
    "encoding/json"
    "fmt"
    "strings"
    "github.com/jmoiron/sqlx"
)

// A used for `sometable` row
type A struct {
    Id int `json:"ID"`
    ValA int `json:"valA"`
    ValB int `json:"valB"`
}

func (a *A) Insert(sqldb *sqlx.DB) (int64, error) {
    var rslt sql.Result
    var err error
    if rslt, err = sqldb.Exec(fmt.Sprintf("INSERT INTO sometable (valA, valB) VALUES (%d, %d)  ", a.ValA, a.ValB)); err != nil {
        return 0, err
    } else if rslt == nil {
        return 0, fmt.Errorf("no result")
    }
    id, err := rslt.LastInsertId()
    if err != nil {
        return 0, err
    }
    return id, nil
}

func (a *A) Query(sqldb *sqlx.DB, id int64, columns []string) (err error) {
    var row *sql.Row
    if len(columns) == 0 {
        return nil
    }
    if row = sqldb.QueryRow(fmt.Sprintf("SELECT %s from sometable where ID=%d", strings.Join(columns, ","), id)); err != nil {
        return err
    } else if row == nil {
        return sql.ErrNoRows
    }
    if err = row.Scan(a); err != nil {
        return err
    }
    return nil
}

func main() {
    input := A{
        ValA: 1,
        ValB: 1,
    }
    db, _ := sqlx.Open("mysql", "root:root")
    id, _ := input.Insert(db)
    db.Exec(`
        CREATE TABLE sometable (
            ID int,
            valA varchar(255),
            valA varchar(255),
        );
    `)
    input.ValA = 0
    input.ValB = 0
    input.Query(db, id, []string{"valA"}) // query only one column causing omitted data returned
    output, _ := json.Marshal(input)
    fmt.Println(string(output))
}