func (n *NamedStmt) Queryx(arg interface{}) (*Rows, error) {
	r, err := n.Query(arg)
	if err != nil {
		return nil, err
	}
	return &Rows{Rows: r, Mapper: n.Stmt.Mapper, unsafe: isUnsafe(n)}, err
}
Queryx using this NamedStmt
Any named placeholder parameters are replaced with fields from arg.
package sqlx
import (
	"database/sql"
	"errors"
	"fmt"
	"reflect"
	"strconv"
	"unicode"
	"github.com/jmoiron/sqlx/reflectx"
)
type NamedStmt struct {
	Params      []string
	QueryString string
	Stmt        *Stmt
}
func (n *NamedStmt) Close() error {
	return n.Stmt.Close()
}
func (n *NamedStmt) Exec(arg interface{}) (sql.Result, error) {
	args, err := bindAnyArgs(n.Params, arg, n.Stmt.Mapper)
	if err != nil {
		return *new(sql.Result), err
	}
	return n.Stmt.Exec(args...)
}
func (n *NamedStmt) Query(arg interface{}) (*sql.Rows, error) {
	args, err := bindAnyArgs(n.Params, arg, n.Stmt.Mapper)
	if err != nil {
		return nil, err
	}
	return n.Stmt.Query(args...)
}
func (n *NamedStmt) QueryRow(arg interface{}) *Row {
	args, err := bindAnyArgs(n.Params, arg, n.Stmt.Mapper)
	if err != nil {
		return &Row{err: err}
	}
	return n.Stmt.QueryRowx(args...)
}
func (n *NamedStmt) MustExec(arg interface{}) sql.Result {
	res, err := n.Exec(arg)
	if err != nil {
		panic(err)
	}
	return res
}