How Linq query fetch data from multiple tables without using join

Question

I have 3 tables in my database which have no relation with each other. what i want is to implement the search operation on my website. So that when a word is submit in search box the query go through all the tables and fetch the data wherever it find that word. I can fetch the data from single table.

    public ActionResult Searchresult(string searchString)
    {
        var article = (from c in db.Tbl_Article select c );
        article = article.Where(s => s.Article_Title.Contains(searchString));

        var blog = (from c in db.Tbl_Blog select c );
        blog = blog.Where(s => s.Blog_Title.Contains(searchString));

        var history = (from c in db.Tbl_History select c);
        history = history.Where(s => s.Title.Contains(searchString));

        var result = article.Select(x => x.Article_Title).Union(blog.Select(x => x.Blog_Title)).Union(history.Select(x => x.Title)).ToList();

    //  ViewBag.result = result.ToString();

        return View(result);
    }

Please don't confuse about what i return in action method, its a very long and unnecessary code for that question.

By using this code I successfully get the search result from one table. Now I want same result from all the tables present in the database. that's where I'm stuck. I searched so many article for that but didn't find any solution that's in the last I myself asking this.

Thanks

Answer 1

This may work

   Public ActionResult Index(string searchString)
    {
     var query1 = (from c in db.TableArticle select c);
       if (!String.IsNullOrEmpty(searchString))
         {
    query1 = query1.Where(s => 
            s.Article_Title.Contains(searchString)
    || s.Article_Description.Contains(searchString) || 
             s.Written_By.Contains(searchString) || 
             s.Organisation.Contains(searchString)
   ||s.Source.Contains(searchString));
            }
    var query2 = (.......);
    var query3 = (.......);

    var finalResult = query1.Select(x => x.columnName).Union(query2.Select(x => x.columnName)).Union(query3.Select(x => x.columnName));
    // OR
    var finalResult = query1.Select(x => x.columnName).Concat(query2.Select(x => x.columnName)).Concat(query3.Select(x => x.columnName));
    }

Answer 2

I have just implemented and checked in my local same query, and it's working fine, The given answer is right by @Khairul Alam,

I have just optimized the code and run the same thing in my local its working fine

var searchString = "School";
        if (!String.IsNullOrEmpty(searchString))
        {
            var query1 = _context.Jobs.Where(s =>
                     s.JobTitle.Contains(searchString)
             || s.LocationDescription.Contains(searchString));

            var query2 = _context.Recruiters.Where(s =>
                    s.RecruiterName.Contains(searchString));

            var query3 = _context.Sectors.Where(s =>
                    s.SectorName.Contains(searchString));
            try
            {
                var finalResult = query1.Select(x => x.JobTitle).Union(query2.Select(x => x.RecruiterName)).Union(query3.Select(x => x.SectorName)).ToList();
            }
            catch (Exception)
            {
                throw;
            }

contain image which output of final result

If you still getting an issue , please share some code or where exactly you getting the error , so we can solve them

hope this will be helpful to you

Thanks