SELECT COUNT(tlast._ident) AS "Total" FROM
(
SELECT * FROM
(
SELECT tlast._ident FROM Prelude_Alert AS top
LEFT JOIN Prelude_Alert AS tlast ON (tlast._ident =top._ident AND tlast._ident BETWEEN 1 AND 281) GROUP BY 1 ORDER BY tlast._ident DESC LIMIT 281
) AS taux
EXCEPT
SELECT * FROM
(
SELECT tlast._ident FROM Prelude_Alert AS top
LEFT JOIN Prelude_Alert AS tlast ON (tlast._ident =top._ident AND tlast._ident BETWEEN 1 AND 281) GROUP BY 1 ORDER BY tlast._ident DESC LIMIT 281
) AS taux WHERE taux._ident IS NULL
) AS tlast
e-REdING. Biblioteca de la Escuela Superior de Ingenieros de Sevilla.
