MySQL의 쿼리 결과에서 사용자 변수를 설정하는 방법은 무엇입니까?

<code class="mysql">SET @user := 123456;
SELECT @group := `group` FROM user WHERE user = @user;
SELECT * FROM user WHERE `group` = @group;</code>

<code class="mysql">CREATE TABLE user (`user` int, `group` int);
INSERT INTO user VALUES (123456, 5);
INSERT INTO user VALUES (111111, 5);</code>

<code class="mysql">SET @user := 123456;
SELECT @group := `group` FROM user WHERE user = @user;
SELECT * FROM user WHERE `group` = @group;

+--------+-------+
| user   | group |
+--------+-------+
| 123456 |     5 |
| 111111 |     5 |
+--------+-------+
2 rows in set (0.00 sec)</code>

<code class="mysql">SET @user := 123456;
SELECT `group` FROM user LIMIT 1 INTO @group;
SELECT * FROM user WHERE `group` = @group;</code>