declare json_string varchar(1024) default '[

    {"rdbms":"MySQL/MariaDB","tag":"Rocks!"},

    {"rdbms":"Oracle Database","tag":"It\'s fine"},

    {"rdbms":"IBM DB2","tag":"Available in z/OS"},

    {"rdbms":"Microsoft SQL Server","tag":"No comments"}

]';

for rdbms in json_query(json_string, '$') do

   -- Do something with current iteration's object.

   select json_value(rdbms, '$.rdbms'), json_value(rdbms, '$.tag');

end for;