func (db *DB) Group(name string) (tx *DB) {
	tx = db.getInstance()

	fields := strings.FieldsFunc(name, utils.IsValidDBNameChar)
	tx.Statement.AddClause(clause.GroupBy{
		Columns: []clause.Column{{Name: name, Raw: len(fields) != 1}},
	})
	return
}

// Having specify HAVING conditions for GROUP BY
//
//	// Select the sum age of users with name jinzhu