The Deep Dark Logic in WHERE Statement

mysql > select user_id, first_name from users;
+---------+------------+
| user_id | first_name |
+---------+------------+
| 1       | admin      |
| 2       | Gordon     |
| 3       | Hack       |
| 4       | Pablo      |
| 5       | Bob        |
+---------+------------+
5 rows in set
Time: 0.006s
mysql > select user_id, first_name from users where user_id=1<1;
+---------+------------+
| user_id | first_name |
+---------+------------+
| 2       | Gordon     |
| 3       | Hack       |
| 4       | Pablo      |
| 5       | Bob        |
+---------+------------+
4 rows in set
Time: 0.007s
mysql >

WHY ???

mysql > select 1=1<1;
+-------+
| 1=1<1 |
+-------+
| 0     |
+-------+
1 row in set
Time: 0.005s
mysql > select 2=1<1;
+-------+
| 2=1<1 |
+-------+
| 1     |
+-------+
1 row in set
Time: 0.005s

My guess

mysql > select True=1
+--------+
| True=1 |
+--------+
| 1      |
+--------+
1 row in set
Time: 0.005s
mysql > select True=0;
+--------+
| True=0 |
+--------+
| 0      |
+--------+
1 row in set
Time: 0.006s

Deep Dark Logic

mysql > select user_id, first_name from users where user_id=1 | 'a'='a';
+---------+------------+
| user_id | first_name |
+---------+------------+
| 2       | Gordon     |
| 3       | Hack       |
| 4       | Pablo      |
| 5       | Bob        |
+---------+------------+
4 rows in set
Time: 0.007s