Following section demonstrates using <hl>GROUP BY</hl> clause.
<sample>
    <pre lang="c#">
		// Table Aliases
        var t0 = new Orders().AsQueryable();

        Odb.SQL.Select(x => 
                        x.From(t0)
                         .GroupBy(t0.EmployeeID)
                         .Fields(t0.EmployeeID, 
                                 x[t0.OrderID].MAX().AS("LastOrderId"))
                    );
    </pre>
    <output>
        SELECT t0.EmployeeID, <hlb>MAX(t0.OrderID) AS LastOrderId</hlb><br />
        FROM [Orders] AS t0 <br />
        <hlb>GROUP BY t0.EmployeeID</hlb>
    </output>
    <fiddle>pWeo94</fiddle>
</sample>