Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>By this: </p> <pre><code> join original in this.NoteDatas on issue.NoteDatas .OrderBy(n =&gt; n.CreatedDate) .Select(n =&gt; n.NoteId) .First() equals original.NoteId </code></pre> <p>you are saying "order by CreatedDate, take first row from the results and check if it equals to NoteId". This is correctly gets rendered to this: </p> <pre><code>INNER JOIN [dbo].[issue_notes] AS [t1] ON (( SELECT TOP (1) [t3].[id] FROM ( SELECT [t2].[id], [t2].[issue_id] FROM [dbo].[issue_notes] AS [t2] ORDER BY [t2].[CreatedDate] ) AS [t3] WHERE [t3].[issue_id] = [t0].[IssueDetailsId] )) = [t1].[id] </code></pre> <p>so <code>t2.id</code> is always same for any outer <code>[t1].[id]</code> but depends on only <code>[t0].[IssueDetailsId]</code></p> <p>Sample: </p> <pre><code> var issues = new Tuple&lt;int, string&gt;[] { new Tuple&lt;int, string&gt;(1, "aaa"), new Tuple&lt;int, string&gt;(2, "bbb") }; var notes = new Tuple&lt;int, DateTime, string&gt;[] { new Tuple&lt;int, DateTime, string&gt;(1, DateTime.Parse("01/01/2001"), "earliest for 1"), new Tuple&lt;int, DateTime, string&gt;(1, DateTime.Parse("02/01/2001"), "middle for 1"), new Tuple&lt;int, DateTime, string&gt;(1, DateTime.Parse("03/01/2001"), "latest for 1"), new Tuple&lt;int, DateTime, string&gt;(2, DateTime.Parse("10/01/2001"), "earliest for 2"), new Tuple&lt;int, DateTime, string&gt;(2, DateTime.Parse("11/01/2001"), "middle for 2"), new Tuple&lt;int, DateTime, string&gt;(2, DateTime.Parse("12/01/2001"), "once more middle for 2"), new Tuple&lt;int, DateTime, string&gt;(2, DateTime.Parse("13/01/2001"), "latest for 2") }; var result = ctx.Set&lt;Parent&gt;().Select(i =&gt; new { i.Id, e = ctx.Set&lt;Child&gt;().Where(c =&gt; c.ParentId == i.Id).OrderBy(c =&gt; c.Name).FirstOrDefault(), l = ctx.Set&lt;Child&gt;().Where(c =&gt; c.ParentId == i.Id).OrderByDescending(c =&gt; c.Name).FirstOrDefault() }); </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POHow to join based on the top 1 id of another table using Linq to SQL?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USLINQ2Vodka
    1. USLINQ2Vodka
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. COUsing `issue.NoteDatas` produces the same output as `this.NoteDatas.Where(n => n.IssueId == issue.IssueId)`. Either way, I'm saying 'get notes for this issue id, order by created date, and take the first note id' but the LINQ to SQL output is doing it a little differently. Even if I try `issue.NoteDatas.OrderBy(n => n.CreatedDate).First().NoteId equals original.NoteId` instead, I see the same output.
      singulars
      1. PO
      1. UStuespetre
    2. CO@tuespetre check update. Is it what you need?
      singulars
      1. PO
      1. USLINQ2Vodka
    3. COThat produces a query that parses, but I'm afraid it's a very inefficient and unusable query, because it evaluates the `SELECT TOP 1 id FROM notes ORDER BY...` for every column I want to select.
      singulars
      1. PO
      1. UStuespetre
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload