power of EF Core LINQ query.cs

// a query on db without any think on database data structure:
// (NullIfEmpty is my function on T[].)
var shardsBounds = context.Storages
                .Select(i => new ShardBounds
                {
                    StorageCode = i.StorageCode,
                    StartDateTime = i.StartDateTime,
                    EndDateTime = i.EndDateTime,
                    PlateReaderIds = i.StoragePlateReaders.Select(i => i.PlateReaderId).ToArray().NullIfEmpty(),
                });
// continue with linq to object
// (the LeftJoin is my function on IEumerable<T>.)
var shards = someObjectsArray.LeftJoin(shardsBounds, i => i.StorageCode, i => i.StorageCode,
                j => new ShardInfo<TContext>
                {
                    ShardSettings = j.Outer,
                    Bounds = j.Inner
                }).ToArray();
                
// translated query: a simple left join :)

/*

SELECT [s].[StorageCode], [s].[StartDateTime], [s].[EndDateTime], [s].[StorageId], [s0].[PlateReaderId], [s0].[StorageId]
FROM [Storages] AS [s]
LEFT JOIN [StoragePlateReaders] AS [s0] ON [s].[StorageId] = [s0].[StorageId]
ORDER BY [s].[StorageId], [s0].[StorageId], [s0].[PlateReaderId]

*/