clausula UNION

[gnzsoloyo]

Tienes que encerrar la union resultante como tabla virtual (subconsulta) y realizar la suma en ella.
Ese sería el camino simple:

Código sql:

SELECT  SUM(TOT) TOTAL
FROM (
SELECT
CAJA.CAJERO AS C,
CAJA.FECHA AS F,
SUM(CAJA.TOTAL) AS TOT,
FROM CAJA
WHERE CAJA.ESTADO='CERRADA'
GROUP BY C
 
UNION
 
SELECT
CAJA.CAJERO AS C,
CAJA.FECHA AS F,
SUM(CAJA.TOTAL) AS TOT,
FROM CAJA
WHERE CAJA.ESTADO='CERRADA' 
GROUP BY F) AS T1;