14.3 Type Conversion in Expression Evaluation| dev.mysql.com
15.2.15.5 Row Subqueries| dev.mysql.com
15.2.15.3 Subqueries with ANY, IN, or SOME| dev.mysql.com
14.4.2 Comparison Functions and Operators| dev.mysql.com
expr| dev.mysql.com
7.1.8 Server System Variables| dev.mysql.com