public static HashSet <ColumnExpression> Gather(Expression expression)
{
ReferencedColumnGatherer gatherer = new ReferencedColumnGatherer();
gatherer.Visit(expression);
return(gatherer.columns);
}
protected override Expression VisitSelect(SelectExpression select)
{
ILookup <TableAlias, ColumnExpression> columns = this.columns;
this.columns = ReferencedColumnGatherer.Gather(select).ToLookup <ColumnExpression, TableAlias>(c => c.Alias);
JoinType?lastJoin = this.lastJoin;
this.lastJoin = null;
Expression expression = base.VisitSelect(select);
this.columns = columns;
this.lastJoin = lastJoin;
return(expression);
}
