toSql method
Implementation
String toSql() {
String sql = 'ON $_column1 = $_column2';
if (_whereClause.wheres.isNotEmpty) {
if (_whereClause.wheres.first.condition == QueryCondition.and) {
sql += ' AND ';
} else if (_whereClause.wheres.first.condition == QueryCondition.or) {
sql += ' OR ';
}
sql += _whereClause.toSql();
}
return sql;
}