Das einzige, was ins Auge springt, ist der Großbuchstabe AS und der gleiche Spaltenalias (standardmäßig unterscheidet mysql nicht zwischen Groß- und Kleinschreibung). Können Sie es so versuchen?
select campo1 as AGR_Number, campo2 as fattura,
campo76 as cod_periodo, campo78 as cod_scenario,
campo11 as origine, campo8 as Stazione,
campo13 as agent, campo30 as AAT_RATE,
sum (cast(campo30 as numeric (9,2))) as AAT_rate_sum
from map_dati_trasformati
where cod_mappatura = 'CARICA_NOL_CSV'
AND CAMPO30 <> 0
GROUP BY campo1, campo2, campo76, campo78, campo11 ,
campo8, campo13, campo30
