function method
Implementation
Wheres function(Function(Transaction) query) {
final transaction = Transaction(where: []);
query(transaction);
final select = transaction.select.toString().replaceAll('[', '').replaceAll(']', '');
q = ' EXISTS ( ';
q += 'SELECT ${select == 'null' ? '*' : select} FROM $tableName ' + (transaction.joinQuery).replaceAll('{NO_SELECTED_TABLE_NAME}', tableName) + Transaction.query(transaction);
q += ' ) ';
return querybuilder(q);
}