public static HashSet <string> Gather(Expression source)
{
var aliasesProduced = new SqlAliasesProduced();
aliasesProduced.Visit(source);
return(aliasesProduced.aliases);
}
protected override Expression VisitSelect(SqlSelectExpression select)
{
var saveIsOuterMostSelect = this.isOuterMostSelect;
try
{
this.isOuterMostSelect = false;
select = (SqlSelectExpression)base.VisitSelect(select);
var canHaveOrderBy = saveIsOuterMostSelect || select.Take != null || select.Skip != null;
var hasGroupBy = select.GroupBy?.Count > 0;
var canReceiveOrderings = canHaveOrderBy && !hasGroupBy && !select.Distinct && !SqlAggregateChecker.HasAggregates(select);
var hasOrderBy = select.OrderBy?.Count > 0;
if (hasOrderBy)
{
PrependOrderings(select.OrderBy);
}
var columns = select.Columns;
var orderings = canReceiveOrderings ? this.gatheredOrderings : (canHaveOrderBy ? select.OrderBy : null);
var canPassOnOrderings = !saveIsOuterMostSelect && !hasGroupBy && !select.Distinct && (select.Take == null && select.Skip == null);
if (this.gatheredOrderings != null)
{
if (canPassOnOrderings)
{
var producedAliases = SqlAliasesProduced.Gather(select.From);
var project = RebindOrderings(this.gatheredOrderings, select.Alias, producedAliases, select.Columns);
this.gatheredOrderings = null;
PrependOrderings(project.Orderings);
columns = project.Columns;
}
else
{
this.gatheredOrderings = null;
}
}
if (orderings != select.OrderBy || columns != select.Columns)
{
select = new SqlSelectExpression(select.Type, select.Alias, columns, select.From, select.Where, orderings, select.GroupBy, select.Distinct, select.Skip, select.Take, select.ForUpdate);
}
return(select);
}
finally
{
this.isOuterMostSelect = saveIsOuterMostSelect;
}
}
public static HashSet<string> Gather(Expression source)
{
var aliasesProduced = new SqlAliasesProduced();
aliasesProduced.Visit(source);
return aliasesProduced.aliases;
}