using HQL to concatenate strings from multiple rows

Consider a table 开发者_如何学Cholding names, with three rows:

Peter Paul Mary

using NHibernate HQL I want to retrieve all the names as a single string "Peter, Paul, Mary" to put it inside a single DTO object field. is there a way to do this kind of concatenation?

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No, there isn't.

It's not possible to do string column aggregation in SQL, except maybe by using specific RDBMS features.

Just bring all the names and concatenate them client-side,

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It is too simple to implement this in C#, so it's not worth to try too hard to tweak NHibernate to do it (you may use functions or formula or ...)

class MyDto
{
  string Name1 { get; set; }
  string Name2 { get; set; }
  string Name3 { get; set; }

  string Names
  { 
    get 
    {
      return string.Format("{0}, {1}, {2}", Name1, Name2, Name3)
    }
  }
}