Expressions and columns need toStringWithQueryAlias()

[lukehutch]

Right now columns have a queryAlias, but the toString method doesn't use the alias:

/// Abstract class representing a database [Column]. Subclassed by the different
/// supported column types such as [ColumnInt] or [ColumnString].
abstract class Column<T> {
  /// Corresponding dart [Type].
  final Type type;

  final String _columnName;

  /// Name of the [Column].
  String get columnName => _columnName;

  /// Table that column belongs to.
  final Table table;

  /// Query alias for the [Column].
  String get queryAlias => '${table.queryPrefix}.$_columnName';

  /// Creates a new [Column], this is typically done in generated code only.
  Column(
    this._columnName,
    this.table,
  ) : type = T;

  @override
  String toString() {
    return '"${table.queryPrefix}"."$_columnName"';
  }
}

Expression.toString just calls Column.toString:

/// Database expression for a column.
abstract class ColumnExpression<T> extends Expression {
  // ...
  String get _getColumnName {
    if (column is! ColumnCount) {
      return column.toString();
    }
    // ...
}

abstract class _TwoPartColumnExpression<T> extends ColumnExpression<T> {
  Expression other;

  _TwoPartColumnExpression(super.column, this.other);

  @override
  List<Column> get columns => [...super.columns, ...other.columns];

  @override
  String toString() {
    return '$_getColumnName $operator $other';
  }
}

The problem with this is that for custom joins, I can't use Expression.toString to specify where clauses if the columns are aliased.

Really all columns should always be aliased (except for the outermost table)... so it would be nice to have a .toStringWithQueryAlias in both expressions and columns, which builds the same expression, but with the query alias "tableName.columnName", not the "tableName"."columnName" naming.