Why is the result of `select 'a'=0;` 1?

Question

mysql> SELECT \'a\'=\'b\'=\'c\';
+-------------+
| \'a\'=\'b\'=\'c\' |
+-------------+
|           1 |
+-------------+
mysql> select \'a\'=0, \'b\'=\'c\';
+---         


        

Answer 1

I believe MySQL calls atoi() or something similar on the string 'a', which equals 0. What does select 'a'=1 give?