func (groupBy GroupBy) Name() string {
	return "GROUP BY"
}

// Build build group by clause
func (groupBy GroupBy) Build(builder Builder) {
	for idx, column := range groupBy.Columns {
		if idx > 0 {
			builder.WriteByte(',')
		}

		builder.WriteQuoted(column)
	}

	if len(groupBy.Having) > 0 {
		builder.WriteString(" HAVING ")
		Where{Exprs: groupBy.Having}.Build(builder)
	}
}

// MergeClause merge group by clause