Código SQL:
Ver originalSELECT c2.B AS cuenta_alumnos_matriculados, c1.A AS cuenta_alumnos_retirados FROM (SELECT COUNT(ID_Alumno) AS A FROM dataperiodo
WHERE dataperiodo.ID_Estado<>3
GROUP BY dataperiodo.ID_Profesor) AS c1,
(SELECT COUNT(ID_Alumno) AS B FROM dataperiodo
GROUP BY dataperiodo.ID_Profesor) AS c2
WHERE c1.ID_Alumno = c2.ID_Alumno;
Prueba a ver que tal.
Un saludo!