SQL - retrieve variable in Stored Procedure

Below are some examples of retrieve content from a table within a SP:

select @iNumRec = count(*) from XXXX where mess_content like '%test%'

select @MessID = a.mess_id from XXXX as a where a.service_timestamp>'2009-12-31'

select @MessID = a.mess_id from XXXX as a order by service_timestamp desc