func (*Star) IsNullable() bool {
	panic("star is just a placeholder node, but IsNullable was called")
}
IsNullable implements the Expression interface.
package expression
import (
	"fmt"
	"github.com/src-d/go-mysql-server/sql"
)
type Star struct {
	Table string
}
func NewStar() *Star {
	return new(Star)
}
func NewQualifiedStar(table string) *Star {
	return &Star{table}
}
func (*Star) Resolved() bool {
	return false
}
func (*Star) Children() []sql.Expression {
	return nil
}