ESP8266 WiFi网络授时时钟：NTP同步时间，抛弃RTC电池的DIY方案
2026/10/16 7:29:41
selectcolumn1,CONCAT_WS("|",COLLECT_SET(column2))fromthe_tablegroupbycolumn1SQL，对每个groupby的每个group的string进行concat
selectcolumn1,CONCAT_WS("|",COLLECT_SET(column2))fromthe_tablegroupbycolumn1