You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: group_by.go
    path of file: ./repos/scan4all/vendor/gorm.io/gorm/clause
    
    the code of the file until where you have to start completion: package clause

// GroupBy group by clause
type GroupBy struct {
	Columns []Column
	Having  []Expression
}

// Name from clause name
func
    
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)
	}
}