NHibernate.Linq not support string.join with group, throw "The method or operation is not implemented."

[superboy1984]

The sql statement I want to implement is
select log.OPUserId as PutStaffId,max(log.OPUserName) as PutStaffName,**group_concat(log.Id)** as PutLogIdsStr,sum(log.Point) as Point from PromotionAccountPutLog log where .. group by log.OPUserId

var statisticsList = (from log in session.Query<PromotionAccountPutLog>().Where(w => ...)
                           group log by log.OPUserId into g
                           select new PutStaffCommissionStatisticsDto
                           {
                               PutLogIdsStr = string.Join(',', g.Select(s => s.Id)), 
                               //PutLogIdsStr = g.GroupConcat(x => x.Id),
                               PutStaffId = g.Key,
                               PutStaffName = g.Max(x => x.OPUserName),
                               Point = g.Sum(s => s.Point),
                               ...
                         }).ToList();

then i try [LinqExtensionMethod("group_concat")], but throw "must be reducible node"

public static class CustomLinqExtensions
    {
        [LinqExtensionMethod("group_concat")]
        public static string GroupConcat<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector)
        {
            throw new NotImplementedException();
        }
    }

nhiberante 5.4.2, mysql 8.0.31

[superboy1984]

efcore supports string.join from version 7.0，and MySql.EntityFrameworkCore 7.0.0 can transate string.Join(',', g.Select(s => s.Id)) with mysql funcation group_concat.
bellow Function Mappings of the Microsoft SQL Server Provider:
https://learn.microsoft.com/en-us/ef/core/providers/sql-server/functions