How to include the value of the query parameter in the email body using sp_send_dbmail
You can set the body of the email to be the query that you want and send the results as an attachment. For example:

DECLARE @sql_cmd NVARCHAR(max) = 
'SELECT COUNT(*) FROM AdventureWorks2012.Production.WorkOrder
              WHERE DueDate &gt; ''2004-04-30''
              AND  DATEDIFF(dd, ''2004-04-30'', DueDate) &lt; 2';
EXEC msdb.dbo.sp_send_dbmail
@profile_name = 'Adventure Works Administrator',
@recipients = 'danw@Adventure-Works.com',
@query =  @sql_cmd,
@body = @sql_cmd,
@subject = 'Work Order Count',
@attach_query_result_as_file = 1 ;


Sources:

http://msdn.microsoft.com/en-us/library/ms190307.aspx