Ayuda con query

[David]

Puedes probar hacerlo con subconsultas:

Código MySQL:

SELECT
    t1.*,
    (SELECT COUNT(t2.idt1) FROM t2 WHERE t2.idt1 = t1.id) c1,
    (SELECT COUNT(t3.idt1) FROM t3 WHERE t3.idt1 = t1.id) c2,
    (SELECT COUNT(t4.idt1) FROM t4 WHERE t4.idt1 = t1.id) c3
FROM t1;