/// <summary>
/// Creates a new <see cref="AliasNode"/> to wrap the results of a subquery with a different alias
/// </summary>
/// <param name="select">The subquery to wrap the results of</param>
/// <param name="identifier">The alias to use for the subquery</param>
public AliasNode(SelectNode select, Identifier identifier)
{
ColumnSet.AddRange(select.ColumnSet);
Source = select.Source;
Alias = identifier.Value;
// Check for duplicate columns
var duplicateColumn = select.ColumnSet
.GroupBy(col => col.OutputColumn, StringComparer.OrdinalIgnoreCase)
.Where(g => g.Count() > 1)
.FirstOrDefault();
if (duplicateColumn != null)
{
throw new NotSupportedQueryFragmentException($"The column '{duplicateColumn.Key}' was specified multiple times", identifier);
}
}