Problemas unir dos tablas

[quimfv]

Código MySQL:

SELECT s.asistente ,
SUM( IF( DATE( s.fe_inst_comp ) = '2014-05-26', 1, 0 ) ) AS CDProgramados,
SUM( IF( DATE( s.fe_inst_comp ) < '2014-05-26' AND s.inst != 'si', 1, 0 ) ) AS Bli,
SUM( IF( DATE( s.fe_inst_comp ) = '2014-05-26' AND s.inst = 'si', 1, 0 ) ) AS CDInstalados,
SUM( IF( DATE( r.fe_inst_comp) = '2014-05-25' AND r.reprogramacion <> '0' AND r.reprogramacion IS NOT NULL  , 1, 0 )) AS CDReprogramados
FROM seguimiento s
LEFT JOIN reprogramaciones r ON s.asistente = r.asistente
GROUP BY s.asistente
 

Y ahora?