MySQL - Ayuda en consulta LIKE

set p_findValue='marc';

SELECT *

FROM Users

WHERE userName= p_findValue OR firstName like p_findValue+'%' OR email=p_findValue;

set p_findValue='marc%';

SELECT *

FROM Users

WHERE userName= p_findValue OR firstName like p_findValue OR email=p_findValue;

set p_findValue='marc';

SELECT *

FROM Users

WHERE userName= p_findValue OR firstName like concat(p_findValue,'%') OR email=p_findValue;