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晚上好，我两天试图解决这个问题，但一无所获。我怀疑这是一个错误，有人可以帮助我吗？我收到以下错误消息。

“where 子句”中的未知列“Distinct1.nCdSite”

[MySqlException (0x80004005): 'where 子句'中的未知列 'Distinct1.nCdSite'] MySql.Data.MySqlClient.MySqlStream.ReadPacket() +501 MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId) +450 MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force) +136 MySql.Data.MySqlClient.MySqlDataReader.NextResult() +1269 MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior 行为) +2528 MySql.Data。 Entity.EFMySqlCommand.ExecuteDbDataReader（CommandBehavior 行为）+22。. .

我有以下代码：

模型：

[Table("pagina")] 
public class pagina 
{ 
    [Key] 
    public long nCdPagina { get; set; } 
    public long nCdVisitante { get; set; } 
    public string sDsUrlReferencia { get; set; } 
    public string sDsPalavraChave { get; set; } 
    public string sDsTitulo { get; set; } 

    [ForeignKey("nCdVisitante")] 
    public visitante visitante { get; set; } 
} 

public class retorno 
{ 
    public long Key { get; set; } 
    public int Online { get; set; } 
} 

[Table("site")] 
public class site 
{ 
    [Key] 
    public long nCdSite { get; set; } 
    public string sDsTitulo { get; set; } 
    public string sDsUrl { get; set; } 
    public DateTime tDtCadastro { get; set; } 
} 

[Table("visitante")] 
public class visitante 
{ 
    [Key] 
    public long nCdVisitante { get; set; } 
    public long nCdSite { get; set; } 
    public string sDsIp { get; set; } 
    public DateTime tDtCadastro { get; set; } 
    public DateTime tDtAtualizacao { get; set; } 

    [ForeignKey("nCdSite")] 
    public site site { get; set; } 
}

询问：

return (from pag in this.context.pagina.Include("visitante").Include("site") 
    group pag by pag.visitante.nCdSite into g 
    select new retorno 
    { 
        Key = g.Key, 
        Online = g.Select(e => e.visitante.sDsIp).Distinct().Count() 
    }).ToList<retorno>();

问题仅发生在我放置Distinct(). Count()如果更不用说完美地工作了。

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0 回答 0