Seems like its in one of OSURS_XXX_EntityName
Is there a way to find out exactly which Entity in OS belongs to which SQL Table, so I can do some select queries in the back end
Something like the SQL below will help you find the table name by entity name. Run it in the outSystems database.
SELECT [PHYSICAL_TABLE_NAME] ,[NAME] FROM [OutSystems].[dbo].[ossys_Entity] where name = 'your entity name' and ESPACE_ID = your espace id
you can find the ESPACE_ID in [OutSystems].[dbo].[ossys_Espace]
Yes Fabian is right you can get the physical table name from ossys_entity.