func (c *Count) Resolved() bool {
	if _, ok := c.Child.(*expression.Star); ok {
		return true
	}
	return c.Child.Resolved()
}
Resolved implements the Expression interface.
package aggregation
import (
	"fmt"
	"github.com/mitchellh/hashstructure"
	"github.com/src-d/go-mysql-server/sql"
	"github.com/src-d/go-mysql-server/sql/expression"
)
type Count struct {
	expression.UnaryExpression
}
func NewCount(e sql.Expression) *Count {
	return &Count{expression.UnaryExpression{Child: e}}
}
func (c *Count) NewBuffer() sql.Row {
	return sql.NewRow(int64(0))
}
func (c *Count) Type() sql.Type {
	return sql.Int64
}
func (c *Count) IsNullable() bool {
	return false
}