从实体的数字字段中选择最大数量（Dynamics CRM 2016）

Question

What is the best way to retrieve the maximum value from a numeric field in an entity? Something like this in SQL Server: Select MAX(NumbericFieldName) From TableName .

I tried this:

var documentno = XrmContext.CreateQuery("nychro_traportaldocumentupload").Max(c => c.GetAttributeValue<Int32?>("nychro_portaldocumentreviewid"));

But I get the error "MAX is not supported"

What is the best way to resolve this?

Answer 1

The following linq code, should be able to accomplish your requirement:

var documentno = (for a in XrmContext.CreateQuery("nychro_traportaldocumentupload")
                 orderby a.nychro_portaldocumentreviewid descending
                 select a).FirstOrDefault()

Answer 2

You have to use fetchxml query & do a FetchExpression to fetch the result.

<fetch distinct='false' mapping='logical' aggregate='true'> 
    <entity name='nychro_traportaldocumentupload'> 
       <attribute name='nychro_portaldocumentreviewid' alias='nychro_portaldocumentreviewid_max' aggregate='max' /> 
    </entity> 
</fetch>