Is there a better way to marshal sql rows?

I have the following struct:

type MyTable struct{
  DBColA []byte `db:"cola" json:"-"`
  ColA string `json:"cola"`
  DBColB []byte `db:"colb" json:"-"`
  ColB string `json:"colb"`
}

I map to []byte [to better handle null values in my sql][1]

When I grab the rows I need to output it as json. In order to do that I convert []byte to string:

var rows []*MyTable
if _, err := Session.Select(&rows, sql, args...); err != nil {
	log.Println(err)
}
for _, row := range rows{
   row.ColA = string(row.DBColA)
   row.ColB = string(row.DBColB)
}
w.Header().Set("Content-Type", "application/json")
if err := json.NewEncoder(w).Encode(rows); err != nil {
  http.Error(w, err.Error(), http.StatusInternalServerError)
}

It seems very inefficient to have DBColA and ColA in my struct and then converting DBColA to a string....I have a lot of columns. Is there a better way?

  [1]: https://github.com/go-sql-driver/mysql/wiki/Examples

Have you tried gosqljson in https://github.com/elgs/gosqljson ?

See example:

	package main

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

	func main() {
		ds := "username:password@tcp(host:3306)/db"
		db, err := sql.Open("mysql", ds)
		defer db.Close()

		if err != nil {
			fmt.Println("sql.Open:", err)
		}

		theCase := "lower" // "lower" default, "upper", camel

		a, _ := gosqljson.QueryDbToArrayJson(db, theCase, "SELECT ID,NAME FROM t LIMIT ?,?", 0, 3)
		fmt.Println(a)
		// [["id","name"],["0","Alicia"],["1","Brian"],["2","Chloe"]]

		m, _ := gosqljson.QueryDbToMapJson(db, theCase, "SELECT ID,NAME FROM t LIMIT ?,?", 0, 3)
		fmt.Println(m)
		// [{"id":"0","name":"Alicia"},{"id":"1","name":"Brian"},{"id":"2","name":"Chloe"}]

	}