CREATE PROCEDURE prepare_data()
BEGIN
    DECLARE i INT DEFAULT 1;
    DECLARE emailString CHAR(16) DEFAULT 'test';


    WHILE i < 100
        DO
            SET emailString = CONCAT(emailString, CAST(i AS CHAR(16)), '@test.de');
            INSERT INTO webshop.user(is_active, name, lower_name, email)
            VALUES ('1', 'harry', 'potter', emailString);
            SET i = i + 1;
        end while;
end;

#CALL prepare_data();