select B.name from (
select distinct A1.user_id1 user_id from
(select A1.user_id user_id1,A1.skill_id from T_USER_SKILL A1 Where A1.skill_id = 1) A1 inner join
(select A2.user_id user_id4,A2.skill_id from T_USER_SKILL A2 Where A2.skill_id = 2) A4
on A1.user_id1 = A4.user_id4
) A left join T_USER B on A.user_id = B.user_id
こんな感じでいいでしょう。
例を2つほど
該当するスキルを単純に数える方法
SELECT B.name FROM ( SELECT user_id FROM T_USER_SKILL WHERE skill_id in (1, 2) GROUP BY user_id HAVING count(*) = 2 ) A LEFT JOIN T_USER B ON A.user_id = B.user_id ;
該当するスキルをAND条件で繋ぐ方法
SELECT B.name FROM ( SELECT A1.user_id FROM T_USER_SKILL A1 LEFT JOIN T_USER_SKILL A2 ON A2.user_id = A1.user_id WHERE A1.skill_id = 1 AND A2.skill_id = 2 ) A LEFT JOIN T_USER B ON A.user_id = B.user_id ;