over method

Expr<T> over({ List<Expr<Object?>> partitionBy = const [], List<OrderTerm> orderBy = const [], WindowFrame? frame, })

Turns an aggregate into a window expression.

Partition and ordering expressions cannot contain nested windows. The selected database must support window functions.

Implementation

Expr<T> over({
  List<Expr<Object?>> partitionBy = const [],
  List<OrderTerm> orderBy = const [],
  WindowFrame? frame,
}) {
  final function = unwrapStorage(expressionNode);
  if ((function is! FunctionNode && function is! DecimalAverage) ||
      !aggregate(function)) {
    throw const OrmException(
      'QUERY.WINDOW',
      'over() applies to an aggregate expression.',
    );
  }
  if ([
    ...partitionBy.map((e) => e.expressionNode),
    ...orderBy.map((o) => o.expression.expressionNode),
  ].any(window)) {
    throw const OrmException(
      'QUERY.WINDOW',
      'Window partition/order expressions cannot contain another window.',
    );
  }
  return Expr.internal(
    WindowNode(
      function,
      List.unmodifiable(partitionBy),
      List.unmodifiable(orderBy),
      frame,
    ),
    codec,
  );
}