CODE EXAMPLE FOR CSHARP

linq from multiple tables

from p in Product
from c in Catalog
from m in Manufacturer
where c.Id == p.CatalogId && m.Id == p.ManufacturerId && p.Active == 1
select new 
    { 
        p.Name,
        p.CatalogId,
        p.ManufacturerId,
        c.Name,
        m.Name 
    };