Dime si funciona
Código SQL:
Ver originalSELECT TU.id_usuario, numero_usuario, x.ScaneosEntrada, X.ScaneosSalida
FROM tb_Usuarios TU JOIN
(SELECT A.id_usuario,
SUM(A.num_escaneos) AS ScaneosEntrada,
SUM(B.num_escaneos) AS ScaneosSalida
FROM tb_escaneos A INNER JOIN tb_escaneosSalida B ON A.id_usuario = B.id_usuario
GROUP BY A.id_usuario) AS X
ON X.id_usuario = TU.id_usuario
GROUP BY TU.id_usuario