Neodani...
La clausula WHERE siempre va después de especificar la(s) tabla(s) involucradas.
Código SQL:
Ver originalSELECT
home `Local`,
CAST(SUBSTRING_INDEX(`ht`, '-', -1) AS SIGNED) Goles,
away `Visitante`,
CAST(SUBSTRING_INDEX(`ht`, '-', 1) AS SIGNED) Goles
FROM partidos
WHERE CAST(SUBSTRING_INDEX(`ht`, '-', -1) AS SIGNED) > (CAST(SUBSTRING_INDEX(`ht`, '-', 1) AS SIGNED)
;
Precisamente es ahí donde salta el error