SQLize | PHPize | SQLtest

CREATE TABLE contacts ( id INT PRIMARY KEY AUTO_INCREMENT, first_name VARCHAR(50) NOT NULL, last_name VARCHAR(50) NOT NULL, email VARCHAR(255) NOT NULL ); INSERT INTO contacts (first_name,last_name,email) VALUES ('Carine ','Schmitt','carine.schmitt@verizon.net'), ('Jean','King','jean.king@me.com'), ('Peter','Ferguson','peter.ferguson@google.com'), ('Janine ','Labrune','janine.labrune@aol.com'), ('Jonas ','Bergulfsen','jonas.bergulfsen@mac.com'), ('Janine ','Labrune','janine.labrune@aol.com'), ('Susan','Nelson','susan.nelson@comcast.net'), ('Zbyszek ','Piestrzeniewicz','zbyszek.piestrzeniewicz@att.net'), ('Roland','Keitel','roland.keitel@yahoo.com'), ('Julie','Murphy','julie.murphy@yahoo.com'), ('Kwai','Lee','kwai.lee@google.com'), ('Jean','King','jean.king@me.com'), ('Susan','Nelson','susan.nelson@comcast.net'), ('Roland','Keitel','roland.keitel@yahoo.com'); SELECT email, COUNT(email) AS ec FROM contacts GROUP BY email HAVING ec > 1; SELECT c1.email FROM contacts c1 INNER JOIN contacts c2 WHERE c1.id > c2.id AND c1.email = c2.email;