code: func MockView() *model.TableInfo {
  	selectStmt := "select b,c,d from t"
  	col0 := &model.ColumnInfo{
  		State:  model.StatePublic,
  		Offset: 0,
  		Name:   model.NewCIStr("b"),
  		ID:     1,
  	}
  	col1 := &model.ColumnInfo{
  		State:  model.StatePublic,
  		Offset: 1,
  		Name:   model.NewCIStr("c"),
  		ID:     2,
  	}
  	col2 := &model.ColumnInfo{
  		State:  model.StatePublic,
  		Offset: 2,
  		Name:   model.NewCIStr("d"),
  		ID:     3,
  	}
  	view := &model.ViewInfo{SelectStmt: selectStmt, Security: model.SecurityDefiner, Definer: &auth.UserIdentity{Username: "root", Hostname: ""}, Cols: []model.CIStr{col0.Name, col1.Name, col2.Name}}
  	table := &model.TableInfo{
  		Name:    model.NewCIStr("v"),
  		Columns: []*model.ColumnInfo{col0, col1, col2},
  		View:    view,
  	}
  	return table
  }
docs: // MockView is only used for plan related tests.