la probe asi
Código sql:
Ver originalUPDATE (SELECT tel1 FROM contactos UNION SELECT tel2 FROM contactos) AS c
INNER JOIN
(SELECT t1.tel1 AS tel, COUNT(t1.tel1) AS repetidos FROM
(SELECT tel1 FROM contactos UNION SELECT tel2 FROM contactos) t1
GROUP BY t1.tel) t2 ON t2.tel = c.tel1 SET contactos.telefonos_repetidos = t2.repetidos;
y me sale este error:
Uknow column 't1.tel' in group statement