Fix explicit DEFAULT value in insert query

[Wuvist]

It seems that go-mysql-server is not compatible with insert query like:

INSERT INTO `users` (`id`, `deleted`) VALUES (1, DEFAULT)

Whereas DEFAULT is just to specify deleted columns should use column default value explicitly.

The issue could be demostrated using below code:

package main

import (
	dbsql "database/sql"

	sqle "github.com/dolthub/go-mysql-server"
	"github.com/dolthub/go-mysql-server/auth"
	"github.com/dolthub/go-mysql-server/memory"
	"github.com/dolthub/go-mysql-server/server"
	_ "github.com/go-sql-driver/mysql"
)

func main() {
	db, _ := dbsql.Open("mysql", "root:@tcp(127.0.0.1:3307)/test")
	defer db.Close()

	query := `CREATE TABLE users (
  id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  deleted tinyint(1) unsigned NOT NULL DEFAULT '0',
  PRIMARY KEY (id)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4`

	stmt, _ := db.Prepare(query)
	stmt.Exec()

	_, err := db.Exec("INSERT INTO `users` (`id`, `deleted`) VALUES (1, DEFAULT)")
	if err != nil {
		panic(err.Error())
	}

	stmtOut, _ := db.Prepare("SELECT `deleted` FROM `users` WHERE `id` = 1")
	defer stmtOut.Close()

	deleted := true
	err = stmtOut.QueryRow().Scan(&deleted)
	if err != nil {
		panic(err.Error())
	}

	if deleted == true {
		panic("Wrong deleted value")
	}
}

var engine *sqle.Engine

func init() {
	engine = sqle.NewDefault()
	db := memory.NewDatabase("test")
	engine.AddDatabase(db)

	config := server.Config{
		Protocol: "tcp",
		Address:  "localhost:3307",
		Auth:     auth.NewNativeSingle("root", "", auth.AllPermissions),
	}

	s, _ := server.NewDefaultServer(config, engine)

	go s.Start()
}

`db.Exec("INSERT INTO `users` (`id`, `deleted`) VALUES (1, DEFAULT)")` will result in error:

Error 1105: plan is not resolved because of node '*plan.Values'

This pull request should avoid such issue by turning explicit DEFAULT in insert query to implicit.

[zachmu]

Thanks for the contribution!

This looks good, but please add tests:

1. parse_test.go
2. insert_queries.go

And don't forget to run ./format_repo.sh when you're done.

[zachmu]

There can be more than 1 element in ExpressionTuples, need to account for that

[Wuvist]

@zachmu Updated pull request with tests and handles multiple ExpressionTuples.

However, as my method is just to turn explicit DEFAULT to implicit. So, it won't work insertion query test case like this:

{
	Name: "explicit DEFAULT with multiple values different order",
	SetUpScript: []string{
		"CREATE TABLE mytable(id int PRIMARY KEY, v2 int NOT NULL DEFAULT '2', v3 int NOT NULL DEFAULT '3')",
	},
	Assertions: []ScriptTestAssertion{
		{
			Query: "INSERT INTO mytable (id, v2, v3)values (1, DEFAULT, 0), (2, 0, DEFAULT)",
			Expected: []sql.Row{
				{sql.OkResult{RowsAffected: 2}},
			},
		},
		{
			Query: "SELECT * FROM mytable",
			Expected: []sql.Row{
				{1, 2, 0},
				{2, 0, 3},
			},
		},
	},
},

[zachmu]

LGTM, thanks for the changes!

[zachmu]

#527