Requête mysql défectueuse

SELECT 
    col1, 
    case 
        when col2='a' then 'on affiche coucou' 
        when col2='b' then 'on affiche bonjour' 
    else 'on affiche autre chose'
    end AS 'nom de la colonne'
FROM
    table

SELECT 
    id.ref_cat,
    rel.ref_bCat,
    id.nom,
    id.type,
    CASE id.type 
        WHEN 'b' THEN bcg.outFocus
        WHEN 's' THEN scg.outFocus
        ELSE 'Erreur'
    END AS outFocus
FROM
    cat_id id
        INNER JOIN cat_status as st using (ref_cat)
        LEFT OUTER JOIN cat_rel as rel using (ref_cat)
        LEFT JOIN bCat_config bcg using (ref_cat)
        LEFT join sCat_config scg using (ref_cat)
WHERE
    st.status!=0 
ORDER BY
    rel.ref_bCat