-- Diferencia entre GROUP BY  y  DISTINCT

SELECT distinct(firstname) FROM datasources.test;
EXPLAIN SELECT DISTINCT(firstname) FROM datasources.test;

SELECT firstname FROM datasources.test GROUP BY firstname;
EXPLAIN SELECT firstname FROM datasources.test GROUP BY firstname;

-- Definición de las tablas y datos de prueba

CREATE TABLE test (
    firstname text,
    codigo1 text,
    codigo2 text,
    codigo3 text
);



INSERT INTO test VALUES ('Juan', '2565368308', NULL, '35763');
INSERT INTO test VALUES ('Juan', '87728636342562659891', '2565188276', '35801');
INSERT INTO test VALUES ('Mohamad', '25653346402565334648', '2565334647', '35801');
INSERT INTO test VALUES ('Joel', '2059330320', '2059336400', '35205');
INSERT INTO test VALUES ('William', '2058700123', '2058700227', '35209');
INSERT INTO test VALUES ('William', '2059789339', '2058700227', '35594');
INSERT INTO test VALUES ('William', '2058700123', '2058700227', '35202');
INSERT INTO test VALUES ('Elia', '2516079797', '25160797612516390940', '36608');
INSERT INTO test VALUES ('Elia', '2516079797', '2516390940', '36532');
INSERT INTO test VALUES ('Elia', '2516079797', '2516390940', '36608');
INSERT INTO test VALUES ('Elia', '2516079797', '2516390940', '36545');
INSERT INTO test VALUES ('Ahmed', '3342157283', NULL, '36106');
INSERT INTO test VALUES ('Ahmed', '3343832279', '3343832402', '36037');
INSERT INTO test VALUES ('Hussein', '2059399107', '2059399821', '35233');
INSERT INTO test VALUES ('Ayman', '3344090076', NULL, '36106');
INSERT INTO test VALUES ('Ayman', '3343832279', '3343832402', '36037');
INSERT INTO test VALUES ('Ayman', '3342228466', '3344271525', '36420');
INSERT INTO test VALUES ('Donald', '2057155583', '2057155795', '35243');
INSERT INTO test VALUES ('Donald', '2057835121', NULL, '35064');
INSERT INTO test VALUES ('Donald', '2054817160', NULL, '35021');
INSERT INTO test VALUES ('Donald', '2059303268', '2059303271', '35210');
INSERT INTO test VALUES ('Matthew', '2059396890', '2059396895', '35205');
INSERT INTO test VALUES ('Matthew', '2054877730', '2054877929', '35594');
INSERT INTO test VALUES ('Edward', '2052214705', '2052210489', '35501');
INSERT INTO test VALUES ('Richard', '2058772535', '2059308014', '35209');
INSERT INTO test VALUES ('Richard', '2059308010', '2059308014', '35209');
INSERT INTO test VALUES ('Richard', '2059308020', '2059308024', '35213');
INSERT INTO test VALUES ('William', '3346120391', '3346120394', '36111');
INSERT INTO test VALUES ('Charles', '2059546591', NULL, '35215');
INSERT INTO test VALUES ('Charles', '2053334500', '2053334522', '35476');
INSERT INTO test VALUES ('Babatunde', '3342779868', NULL, '36117');
INSERT INTO test VALUES ('Babatunde', '3344099090', '3344099669', '36117');
INSERT INTO test VALUES ('Caroline', '3342779868', NULL, '36117');
INSERT INTO test VALUES ('Caroline', '3344099242', '3344099186', '36117');
INSERT INTO test VALUES ('Edward', '3033722929', NULL, '80246');
INSERT INTO test VALUES ('Edward', '2059345304', '2059341477', '35294');
INSERT INTO test VALUES ('Gary', '2058018000', '2058018614', '35233');
INSERT INTO test VALUES ('John', '3348262901', '3348262830', '36830');
INSERT INTO test VALUES ('James', '2058704030', '2058704083', '35209');
INSERT INTO test VALUES ('Pippa', '25655146002565365511', '25655146992565514585', '35801');
INSERT INTO test VALUES ('Leslie', '20593996532059396914', '2059399972', '35233');
INSERT INTO test VALUES ('Eugene', '2566541766', NULL, '35603');
INSERT INTO test VALUES ('Eugene', '2563530626', '2563502609', '35601');
INSERT INTO test VALUES ('Eugene', '2563530626', '2563502609', '35601');
INSERT INTO test VALUES ('Stefan', '4786337677', '4786337669', '31201');
INSERT INTO test VALUES ('Amy', '2059919236', NULL, '35242');
INSERT INTO test VALUES ('Amy', '6153252614', NULL, '35205');
INSERT INTO test VALUES ('Charles', '2058792221', '2058790615', '35223');
INSERT INTO test VALUES ('Charles', '8709094', NULL, '35242');
INSERT INTO test VALUES ('Christopher', '3347498303', '33474552433343642251', '36801');
INSERT INTO test VALUES ('Curtis', '2513430040', '2513430069', '36608');
INSERT INTO test VALUES ('Douglas', '3363799488', '3366231200', '27408');
INSERT INTO test VALUES ('Douglas', '25639805052568958148', '2564898148', '35758');
INSERT INTO test VALUES ('George', '2053384313', '2053388555', '35234');
INSERT INTO test VALUES ('George', '20525060612052506000', '20525089572052506848', '35234');
INSERT INTO test VALUES ('George', '2053384313', '2052508957', '35125');
INSERT INTO test VALUES ('George', '2054877730', '2054877929', '35594');
INSERT INTO test VALUES ('Gregory', '2563556414', '2563556646', '35602');
INSERT INTO test VALUES ('Gregory', '25635564144237787000', '2563556646', '35601');
INSERT INTO test VALUES ('James', '2055024020', '20525068482055024022', '35234');
INSERT INTO test VALUES ('James', '9017471000', NULL, '38120');
INSERT INTO test VALUES ('James', '9017471000', NULL, '35213');
INSERT INTO test VALUES ('James', '205250600020525081002052506845', '20525068482052508995', '35234');
INSERT INTO test VALUES ('Jeffrey', '3348343671', '3348342185', '36106');
INSERT INTO test VALUES ('Jon', '3345661270', '3345661296', '36081');
INSERT INTO test VALUES ('Kynard', '3342643434', '3348349071', '36106');
INSERT INTO test VALUES ('Paul', '3347934625', NULL, '36305');
INSERT INTO test VALUES ('Paul', '3347932312', '3346710484', '36302');
INSERT INTO test VALUES ('Paul', '3347932312', '3346710484', '36305');
INSERT INTO test VALUES ('William', '2467931', NULL, '37660');
INSERT INTO test VALUES ('William', '2055991020', '2055991029', '35213');
INSERT INTO test VALUES ('Jon', '2053979000', '2053979001', '35209');
INSERT INTO test VALUES ('Jon', '2056632569', '2056641727', '35007');
INSERT INTO test VALUES ('Jerry', '2567647721', '25676487882567648589', '35630');
INSERT INTO test VALUES ('Mark', '2567393838', '2567398350', '35058');
INSERT INTO test VALUES ('Oluyinka', '3342632301', '3342644353', '36104');
INSERT INTO test VALUES ('Oluyinka', '3342773473', '3342773473', '36116');
INSERT INTO test VALUES ('Anthony', '6012490013', '6012490592', '39648');
INSERT INTO test VALUES ('Harry', '2058714274', '2058714301', '35209');
INSERT INTO test VALUES ('David', '20593978382059337838', '2059330951', '35205');
INSERT INTO test VALUES ('Kendral', '8504364563', NULL, '32501');
INSERT INTO test VALUES ('Arun', '8033245280', '8033280270', '29732');
INSERT INTO test VALUES ('Brian', '8008228816', NULL, '35233');
INSERT INTO test VALUES ('Brian', '2058772888', '2058772039', '35209');
INSERT INTO test VALUES ('William', '2516267162', NULL, '36527');
INSERT INTO test VALUES ('William', '2514352646', '2514356478', '36607');
INSERT INTO test VALUES ('Syed', '2055623700', '2055623769', '35404');
INSERT INTO test VALUES ('Syed', '2055623700', '2053496488', '35401');
INSERT INTO test VALUES ('Kamran', '2513459455', NULL, '36608');
INSERT INTO test VALUES ('Caesar', '2514333344', '2514334052', '36607');
INSERT INTO test VALUES ('Anupam', '2052621711', NULL, '35223');
INSERT INTO test VALUES ('Anupam', '2057319050', NULL, '35233');
INSERT INTO test VALUES ('Anupam', '6175257315', NULL, '02115');
INSERT INTO test VALUES ('Anupam', '2563502211', NULL, '35601');
INSERT INTO test VALUES ('Angelo', '3342713100', NULL, '36117');
INSERT INTO test VALUES ('Angelo', '3342713100', '3342714669', '36117');
INSERT INTO test VALUES ('Edith', '3342659225', '3342406653', '36106');
INSERT INTO test VALUES ('Michelle', '3342884624', '3342803628', '36111');
INSERT INTO test VALUES ('Michelle', '3348262500', '3348266700', '36830');
INSERT INTO test VALUES ('Shelinder', '2563821401', '2563821402', '35801');