Group by/extract como fazer?

estou precisando que alguem me ajude nesse Select, preciso de uma saida
assim:

mes/ano total
01/2000 40
02/2000 50

o campo mes/ano, quero que seja agrupado, MAS a clausula group by nao
aceita o extract, nem o nome dado ao campo MESANO. Verifiquei que no Oracle isso e possivel, com o extract, sera que no interbase isso nao e possivel?

SELECT cast(EXTRACT(YEAR FROM E.DIST_DATE) as integer) || ´/´ ||
cast(EXTRACT(MONTH FROM E.DIST_DATE) as integer) MESANO
FROM ESMART E
GROUP BY EXTRACT(YEAR FROM E.DIST_DATE) || ´/´ ||
EXTRACT(MONTH FROM E.DIST_DATE)

SELECT cast(EXTRACT(YEAR FROM E.DIST_DATE) as integer) || ´/´ ||
cast(EXTRACT(MONTH FROM E.DIST_DATE) as integer) MES
FROM ESMART E
GROUP BY MESANO