Código SQL [-]SELECT * FROM tabla1 left join tabla2 on tabla1.idtabla1=tabla2.idtabla1 where tabla1.campo1>3 and ((tabla2.campoA=0) or (tabla2.idtabla2 is null and campoA is null)
SELECT * FROM tabla1 left join tabla2 on tabla1.idtabla1=tabla2.idtabla1 where tabla1.campo1>3 and ((tabla2.campoA=0) or (tabla2.idtabla2 is null and campoA is null)