MySQL 的函数和操作符
https://dev.mysql.com/doc/refman/8.0/en/functions.html
无类型操作符:
https://dev.mysql.com/doc/refman/8.0/en/non-typed-operators.html
流程控制函数:条件函数
https://dev.mysql.com/doc/refman/8.0/en/flow-control-functions.html
算数类函数:
https://dev.mysql.com/doc/refman/8.0/en/numeric-functions.html
日期时间函数:
https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html
字符串函数:
https://dev.mysql.com/doc/refman/8.0/en/string-functions.html
类型转换函数
https://dev.mysql.com/doc/refman/8.0/en/cast-functions.html
聚合函数:
https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html