public RowCursor Evaluate( 
   QueryDef queryDef,
   bool useRecyclingCursor
)

public async Task SimpleQueryDef()
{
    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
        using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file"))))
        {
            QueryDef adaCompilantParksQueryDef = new QueryDef
            {
                Tables = "Park",
                WhereClause = "ADACOMPLY = 'Yes'",
            };

            using (RowCursor rowCursor = geodatabase.Evaluate(adaCompilantParksQueryDef, false))
            {
                while (rowCursor.MoveNext())
                {
                    using (Row row = rowCursor.Current)
                    {
                        Feature feature = row as Feature;
                        Geometry shape = feature.GetShape();

                        String type = Convert.ToString(row["ADACOMPLY"]); // will be "Yes" for each row.

                        try
                        {
                            Table table = row.GetTable(); // Will always throw exception.
                        }
                        catch (NotSupportedException exception)
                        {
                            // Handle not supported exception.
                        }
                    }
                }
            }
        }
    });
}

public async Task JoiningWithWhereQueryDef()
{
    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
        using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file"))))
        {
            QueryDef municipalEmergencyFacilitiesQueryDef = new QueryDef
            {
                SubFields = "EmergencyFacility.OBJECTID, EmergencyFacility.Shape, EmergencyFacility.FACILITYID, FacilitySite.FACILITYID, FacilitySite.FCODE",
                Tables = "EmergencyFacility, FacilitySite",
                WhereClause = "EmergencyFacility.FACNAME = FacilitySite.NAME AND EmergencyFacility.JURISDICT = 'Municipal'",
            };

            using (RowCursor rowCursor = geodatabase.Evaluate(municipalEmergencyFacilitiesQueryDef, false))
            {
                while (rowCursor.MoveNext())
                {
                    using (Row row = rowCursor.Current)
                    {
                        Feature feature = row as Feature;
                        Geometry shape = feature.GetShape();

                        long objectID = Convert.ToInt64(row["EmergencyFacility.OBJECTID"]);
                        String featureCode = Convert.ToString(row["FacilitySite.FCODE"]);

                        IReadOnlyList<Field> fields = feature.GetFields(); //Contains one ArcGIS.Core.Data.Field objects for every subfield
                    }
                }
            }
        }
    });
}

public async Task EvaluatingQueryDefWithOuterJoin()
{
    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
        using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file"))))
        {
            QueryDef queryDefWithLeftOuterJoin = new QueryDef
            {
                Tables = "CommunityAddress LEFT OUTER JOIN MunicipalBoundary on CommunityAddress.Municipality = MunicipalBoundary.Name",
                SubFields = "CommunityAddress.OBJECTID, CommunityAddress.Shape, CommunityAddress.SITEADDID, CommunityAddress.ADDRNUM, CommunityAddress.FULLNAME, CommunityAddress.FULLADDR, CommunityAddress.MUNICIPALITY, MunicipalBoundary.Name, MunicipalBoundary.MUNITYP, MunicipalBoundary.LOCALFIPS",
            };

            using (RowCursor rowCursor = geodatabase.Evaluate(queryDefWithLeftOuterJoin, false))
            {
                while (rowCursor.MoveNext())
                {
                    using (Row row = rowCursor.Current)
                    {
                        Feature feature = row as Feature;
                        Geometry shape = feature.GetShape();

                        int siteAddressId = Convert.ToInt32(row["CommunityAddress.SITEADDID"]);
                        String stateName = Convert.ToString(row["MunicipalBoundary.name"]);
                    }
                }
            }
        }
    });
}

public async Task EvaluatingQueryDefWithInnerJoin()
{
    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
        using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file"))))
        {
            QueryDef queryDef = new QueryDef()
            {
                Tables = "People INNER JOIN States ON People.FK_STATE_ID = States.OBJECTID",
                SubFields = "People.OBJECTID, People.First_Name, People.Last_Name, People.City, States.State_Name"
            };

            using (RowCursor cursor = geodatabase.Evaluate(queryDef))
            {
                while (cursor.MoveNext())
                {
                    using (Row row = cursor.Current)
                    {
                        // Handle row
                    }
                }
            }
        }
    });
}

public async Task EvaluatingQueryDefWithNestedJoin()
{
    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
        using (Geodatabase geodatabase = new Geodatabase(
    new DatabaseConnectionFile(new Uri("path\\to\\sde\\file"))))
        {
            QueryDef queryDef = new QueryDef()
            {
                Tables = "((People INNER JOIN States ON People.FK_STATE_ID = States.OBJECTID) LEFT OUTER JOIN Homes ON People.OBJECTID = Homes.FK_People_ID)",
                SubFields = "People.OBJECTID, People.First_Name, People.Last_Name, States.State_Name, Homes.Address"
            };

            using (RowCursor cursor = geodatabase.Evaluate(queryDef, false))
            {
                while (cursor.MoveNext())
                {
                    using (Row row = cursor.Current)
                    {
                        // Handle row
                    }
                }
            }
        }
    });
}