/// <summary>
/// Initializes a new instance of the <see cref="AggregateSubqueryExpression"/> class.
/// </summary>
/// <param name="groupByAlias">The group by alias.</param>
/// <param name="aggregateInGroupSelect">The aggregate in group select.</param>
/// <param name="aggregateAsSubquery">The aggregate as subquery.</param>
public AggregateSubqueryExpression(TableAlias groupByAlias, Expression aggregateInGroupSelect, ScalarExpression aggregateAsSubquery)
: base(DbExpressionType.AggregateSubquery, aggregateAsSubquery.Type)
{
this.AggregateInGroupSelect = aggregateInGroupSelect;
this.GroupByAlias = groupByAlias;
this.AggregateAsSubquery = aggregateAsSubquery;
}
/// <summary>
/// Updates the scalar.
/// </summary>
/// <param name="scalar">The scalar.</param>
/// <param name="select">The select.</param>
/// <returns></returns>
protected ScalarExpression UpdateScalar(ScalarExpression scalar, SelectExpression select)
{
if (select != scalar.Select)
{
return(new ScalarExpression(scalar.Type, select));
}
return(scalar);
}
/// <summary>
/// Compares the scalar.
/// </summary>
/// <param name="a">A.</param>
/// <param name="b">The b.</param>
/// <returns></returns>
protected virtual bool CompareScalar(ScalarExpression a, ScalarExpression b)
{
return(this.Compare(a.Select, b.Select));
}
/// <summary>
/// Updates the aggregate subquery.
/// </summary>
/// <param name="aggregate">The aggregate.</param>
/// <param name="subquery">The subquery.</param>
/// <returns></returns>
protected AggregateSubqueryExpression UpdateAggregateSubquery(AggregateSubqueryExpression aggregate, ScalarExpression subquery)
{
if (subquery != aggregate.AggregateAsSubquery)
{
return(new AggregateSubqueryExpression(aggregate.GroupByAlias, aggregate.AggregateInGroupSelect, subquery));
}
return(aggregate);
}
/// <summary>
/// Visits the scalar.
/// </summary>
/// <param name="scalar">The scalar.</param>
/// <returns></returns>
protected virtual Expression VisitScalar(ScalarExpression scalar)
{
var select = (SelectExpression)this.Visit(scalar.Select);
return(this.UpdateScalar(scalar, select));
}
