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POLINQ query, selecting latest value with group by - Unsupported method
 

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  1. POLINQ query, selecting latest value with group by - Unsupported method
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    <p>I have this table with fund data values and I want to select the latest values for each fund (FundId). This query is giving me problems though when executed. "Specified method is not supported".</p> <pre><code>var q = from f in ctx.FundDatas group f by f.FundId into g let latestDataItem = g.OrderByDescending(r =&gt; r.DateOfValue).FirstOrDefault() select new { g.Key, LatestDataItem = latestDataItem }; var list = q.ToList(); //Executed and exception is thrown </code></pre> <p>Why wouldn't this order by work? I <strong>don't</strong> want to just get the Key and DateOfValue, if so I would have just skipped the "let" part and made the select like this:</p> <pre><code>select new { g.Key, LatestDateOfValue = g.Max(y=&gt;y.DateOfValue) }; </code></pre> <p>The above works... But I want the whole object of the latest of each fund data items, not just the max date.</p> <p>Here's the inner exception stack trace:</p> <pre><code>[NotSupportedException: Specified method is not supported.] MySql.Data.Entity.SqlGenerator.Visit(DbApplyExpression expression) +28 System.Data.Common.CommandTrees.DbApplyExpression.Accept(DbExpressionVisitor`1 visitor) +25 MySql.Data.Entity.SqlGenerator.VisitInputExpression(DbExpression e, String name, TypeUsage type) +35 MySql.Data.Entity.SelectGenerator.VisitInputExpressionEnsureSelect(DbExpression e, String name, TypeUsage type) +21 MySql.Data.Entity.SelectGenerator.Visit(DbProjectExpression expression) +38 System.Data.Common.CommandTrees.DbProjectExpression.Accept(DbExpressionVisitor`1 visitor) +25 MySql.Data.Entity.SelectGenerator.GenerateSQL(DbCommandTree tree) +60 MySql.Data.MySqlClient.MySqlProviderServices.CreateDbCommandDefinition(DbProviderManifest providerManifest, DbCommandTree commandTree) +376 System.Data.Common.DbProviderServices.CreateCommandDefinition(DbCommandTree commandTree) +125 System.Data.EntityClient.EntityCommandDefinition..ctor(DbProviderFactory storeProviderFactory, DbCommandTree commandTree) +442 </code></pre> <p>I'm running MySQL with .NET connector 6.5.4.0.</p> <p>Edit: Table definition:</p> <pre><code>FundId int(6), PK DateOfValue date, PK Value double(12,6) </code></pre>
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    1. This table or related slice is empty.
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      1. POLINQ query, selecting latest value with group by - Unsupported method
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    1. CO"I have this table with fund data values" - Which table? Did you mean to include a table definition?
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      1. POLINQ query, selecting latest value with group by - Unsupported method
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    2. COThere, table definition added. It's a really simple table with FundId and DateOfValue as keys together and then the actual value as a double.
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    3. COSorry - wasn't suggesting it was needed, just looked as though you had intended to include it.
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