--  lepine_w, select a,b,a+b from (select (subquery1) as a, (subquery2) as b from foo) as x
SELECT
	s1.user,  
    s1.action,
    s1.date_inscription,
	a,
	b,
	a+b

FROM
	(	SELECT (
    				SELECT
    					COUNT( * )
    				FROM
    					jos_chronoforms_si s2
                    WHERE
                    	s2.user=s1.user AND
                        s2.date_inscription = s1.date_inscription AND
                        s2.action = s1.action
    			) as a,
    
    	SELECT (
        			SELECT
    					COUNT( * )
    				FROM
    					jos_chronoforms_si s3
                    WHERE
                    	s3.user=s1.user AND
                        s3.date_inscription = s1.date_inscription AND
                        s3.action = s1.action
        		) as b,
        
        jos_chronoforms_si s1
    )
    
GROUP BY
	s1.user,
    s1.action,
    s1.date_inscription