1. 问题和解决办法
1.1 SELECT 字段中的非聚合函数包裹的字段，必须在 GROUP BY中申明
# SQLSTATE[HY000]: General error: 1064 '`u`.`name`' must be an aggregate expression or appear i[......]# SQLSTATE[HY000]: General error: 1064 '`u`.`name`' must be an aggregate expression or appear i[......]