Exception Running Query - Index was outside the bounds of the array

I’ve the following query:

public class REPORT_PlcsQuery : ICachableQueryScript
{
    public class Data
    {
        public string Name { get; set; }
    }

    public object Run(object[] parameters)
    {
        using (var db = new VisuDb())
        {
            var allData = (from tag in db.Tags
                           where (tag.Name.StartsWith("SRM.") || tag.Name.StartsWith("CS.")) && tag.Name.IndexOf(".", 5) > 0
                           select new Data
                           {
                               Name = tag.Name.Substring(tag.Name.IndexOf(".") + 1, tag.Name.IndexOf(".", 5) - tag.Name.IndexOf(".") - 1)
                           }).ToList().DistinctBy(x => x.Name).OrderBy(x => x.Name).ToList();

            return allData;
        }
    }
}

Exception message: Index was outside the bounds of the array
Stack trace:



at bool LinqToDB.SqlQuery.SqlFunction.Equals(ISqlExpression other, Func comparer)
at bool LinqToDB.SqlQuery.SqlBinaryExpression.Equals(ISqlExpression other, Func comparer)
at bool LinqToDB.SqlQuery.SqlBinaryExpression.System.IEquatable.Equals(?)
at ISqlExpression LinqToDB.SqlProvider.BasicSqlOptimizer.OptimizeBinaryExpression(SqlBinaryExpression be, EvaluationContext context)
at IQueryElement LinqToDB.SqlProvider.BasicSqlOptimizer.OptimizeElement(MappingSchema mappingSchema, IQueryElement element, OptimizationContext optimizationContext, bool withConversion)+(ConvertVisitor visitor, IQueryElement e) => { }
at IQueryElement LinqToDB.SqlProvider.BasicSqlOptimizer.RunOptimization(IQueryElement element, OptimizationContext optimizationContext, BasicSqlOptimizer optimizer, MappingSchema mappingSchema, bool register, Func, IQueryElement, IQueryElement> func)+(ConvertVisitor visitor, IQueryElement e) => { }
at IQueryElement LinqToDB.SqlQuery.ConvertVisitor.ConvertInternal(IQueryElement element) x 2
at T[] LinqToDB.SqlQuery.ConvertVisitor.Convert(T[] arr1, Clone clone)
at IQueryElement LinqToDB.SqlQuery.ConvertVisitor.ConvertInternal(IQueryElement element)
at T LinqToDB.SqlProvider.OptimizationContext.ConvertAll(RunOptimizationContext context, T element, Func, IQueryElement, IQueryElement> convertAction, Func, bool> parentAction)
at IQueryElement LinqToDB.SqlProvider.BasicSqlOptimizer.RunOptimization(IQueryElement element, OptimizationContext optimizationContext, BasicSqlOptimizer optimizer, MappingSchema mappingSchema, bool register, Func, IQueryElement, IQueryElement> func)
at IQueryElement LinqToDB.SqlProvider.BasicSqlOptimizer.OptimizeElement(MappingSchema mappingSchema, IQueryElement element, OptimizationContext optimizationContext, bool withConversion)
at IQueryElement LinqToDB.SqlProvider.BasicSqlOptimizer.ConvertElement(MappingSchema mappingSchema, IQueryElement element, OptimizationContext context)
at void LinqToDB.SqlProvider.BasicSqlBuilder.BuildColumns(SelectQuery selectQuery)
at void LinqToDB.SqlProvider.BasicSqlBuilder.BuildSelectQuery(SqlSelectStatement selectStatement)
at void LinqToDB.SqlProvider.BasicSqlBuilder.BuildSql(int commandNumber, SqlStatement statement, StringBuilder sb, OptimizationContext optimizationContext, int indent, bool skipAlias) x 2
at PreparedQuery LinqToDB.Data.DataConnection+QueryRunner.GetCommand(DataConnection dataConnection, IQueryContext query, IReadOnlyParameterValues parameterValues, bool forGetSqlText, int startIndent)
at ExecutionPreparedQuery LinqToDB.Data.DataConnection+QueryRunner.CreateExecutionQuery(DataConnection dataConnection, IQueryContext context, IReadOnlyParameterValues parameterValues, bool forGetSqlText)
at void LinqToDB.Data.DataConnection+QueryRunner.SetQuery(IReadOnlyParameterValues parameterValues, bool forGetSqlText)
at IDataReader LinqToDB.Data.DataConnection+QueryRunner.ExecuteReader()
at IEnumerable LinqToDB.Linq.QueryRunner.ExecuteQuery(Query query, IDataContext dataContext, Mapper mapper, Expression expression, object[] ps, object[] preambles, int queryNumber)+MoveNext()
at new System.Collections.Generic.List(IEnumerable collection)
at List System.Linq.Enumerable.ToList(IEnumerable source)

Environment details

linq2db version: current Database Server: mssql .NET Framework: net6

[sdanyliv]

https://stackoverflow.com/a/69100842/10646316 Just remove Take.

[sdanyliv]

I have no plans to support DistinctBy before LINQ parsing refactoring is done. Also with linq2db it can be expressed by ROW_NUMBER window function.