aide sur requetes sql

[nadoush.1984]

svp j'ai besoins d'aide sur requête
ne fonctinne pas


create table colloque (ID_colloque varchar (5) , Titre varchar(250) , DateDébut date, Durée int, ID_Local varchar(5) , Président varchar(250) );
create table Conference (ID_conference int, Date date, Heure int, ID_colloque varchar(5), chercheur varchar(250));
create table Localisation (ID_Local varchar(3), Nom varchar(250), Adresse varchar(250), Capacite int);

insert into colloque values (1, 'MLearning', '22-11-2017', 3, 1, 'P1');
insert into colloque values (2, 'Big Data', '12-01-2018', 3, 1, 'R1');
insert into colloque values(3, 'Systemes embarques', '05-04-2018', 3, 2, 'Q1');
insert into colloque values (4, 'Mobile Computing', '15-05-2018', 3, 3, 'P2');

insert into Conference values (1, '22-11-2017', 9, 1, 'CC1');
insert into Conference values (2, '22-11-2017', 14, 1, 'CC2');
insert into Conference values (3, '22-11-2017', 11, 1, 'CC3');
insert into Conference values (4, '23-11-2017', 9, 1, 'CC1');
insert into Conference values (5, '23-11-2017', 11, 1, 'CC4');
insert into Conference values (6, '23-11-2017', 14, 1, 'CC5');
insert into Conference values (7, '23-11-2017', 16, 2, 'CD1');
insert into Conference values (8, '24-11-2017', 14,1, 'CD2');
insert into Conference values (9, '24-11-2017', 11, 2, 'CD3');
insert into Conference values (10, '24-11-2017', 9, 3, 'CD1');
insert into Conference values (11, '24-11-2017', 16, 3, 'CD4');

insert into Localisation values (1, 300, 'Adr1', 400);
insert into Localisation values (2, 200, 'Adr2', 300);
insert into Localisation values (3, 400, 'Adr3', 500);

1ere
SELECT Date FROM conference t, colloque u, Localisation v WHERE t.ID_colloque = u. ID_colloque AND t.chercheur = '%C1' AND u.ID_Local = v.ID_Local AND v.Nom = 1 ;

2eme
Select date from conference joint colloque joint localisation on colloque.ID_colloque=conference.ID_colloque and where chercheur=’CC1’ AND Nom=1 ;