Linq search text using 'and' operator in joined fields from different tables

问题

Thanks NetMage for answering my question in Linq search text using 'and' operator

Now, please let me ask some more complicated:

I have the following tables where localizationdata.EntryId is linked to mascotcategories.Id and mascots.Id depending on the localizationdata.Type value.

`localizationdata` (
  `Id` int(11)`, Type` varchar(45),
  `EntryId` int(11),
  `LanguageId` int(11),
  `Value` varchar(150) }

`mascots` (
  `Id` int(11), `Name` varchar(100),
  `MascotCategoryId` int(11),
  `UserId` varchar(100),


`mascotcategories` (
  `Id` int(11), `CategoryName` varchar(45),
  `IsVisible` bit(1),
  `ParentId` int(11) DEFAULT NULL,
  `SawgrassOnly` bit(1)

I need again to 'AND' search (as in my previous question in the link above) the localizationdata.value which contains the translated word for mascotcategories.CategoryName and mascots.Name.

For example, the user would enter French keywords "bleu ici" in which the 'bleu ' comes from localizationdata.Value that has the translated category name and 'ici' comes from localizationdata.Value too that has the mascot's translated name. I need the mascots that contain both the above words to their name and to their categories' name. Is this feasible?

回答1:

I am not sure how optimal this is, but I believe it works:

First, reduce the two types of localization down to one common type:

var mascotNameLocalized = from ld in db.localizationdata
                          where ld.Type == "mascot"
                          group ld by ld.EntryId into ldg
                          select new { MascotId = ldg.Key, Words = ldg.Select(g => g.Value) };
var mascotCategoriesLocalized = from ld in db.localizationdata
                                where ld.Type == "mascotcategory"
                                join mc in db.mascotcategories on ld.EntryId equals mc.Id
                                join m in db.mascots on mc.Id equals m.MascotCategoryId into mj
                                where mj.Any()
                                from m in mj
                                group ld by m.Id into ldg
                                select new { MascotId = ldg.Key, Words = ldg.Select(g => g.Value) };

Then combine them into one common list:

var mascotsLocalized = from m in mascotNameLocalized.Concat(mascotCategoriesLocalized)
                       group m by m.MascotId into mg
                       select new { MascotId = mg.Key, Words = mg.SelectMany(m2 => m2.Words).ToList() };

Then find all mascots that match all the search terms:

var srch = "bleu ici";
var srchwords = srch.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);

var ans = from m in mascotsLocalized
          where srchwords.All(sw => m.Words.Contains(sw))
          select m.MascotId;

来源：https://stackoverflow.com/questions/45516773/linq-search-text-using-and-operator-in-joined-fields-from-different-tables

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linq