func (c *Column) String() string {
	return ""
}
String implements fmt.Stringer interface.
package table
import (
	"strings"
	"github.com/pingcap/parser/mysql"
	"github.com/pingcap/tidb/types"
	"github.com/pingcap/tidb/util/hack"
	"github.com/zhihu/zetta/pkg/model"
)
type Column struct {
	*model.ColumnMeta
}