SELECT DISTINCT column1, column2, ... FROM table_name;
SELECT DISTINCT ma_colonne FROM nom_du_tableau
SELECT DISTINCT column1, column1, ..... FROM TABLE /*DISTINCT WILL NOT SELECT THE SAME VALUES IN SAME COLUMN*/
SELECT DISTINCT Column_name FROM table_name;
SELECT a.* FROM emails a INNER JOIN (SELECT email, MIN(id) as id FROM emails GROUP BY email ) AS b ON a.email = b.email AND a.id = b.id;