Question

I have the following tables

CREATE TABLE IF NOT EXISTS `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8  ;


CREATE TABLE IF NOT EXISTS `skill` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8  ;

CREATE TABLE IF NOT EXISTS `user_skill` (
  `user_id` int(11) NOT NULL,
  `skill_id` int(11) NOT NULL ,
  PRIMARY KEY (`user_id`,`skill_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8  ;

The table user_skill acts as the many-to-many table. Now i want to select all users having skill_ids atleast 1 & 2. How can i do that in mysql

Answer 1

select u.id, u.name
from `user` u
inner join `user_skill` us on u.id = us.user_id
where us.skill_id in (1, 2)
group by u.id
having count(distinct us.skill_id) = 2