MySQL拼接字符串，group_concat 伴随所有集合为空

https://cloud.tencent.com/developer/article/2161664?areaSource=102001.19&traceId=cDYsy2PX8aGCMB9v5UvjN

https://www.jb51.net/article/275354.htm?eqid=bd28fdb3000095c8000000066479c12e

All elements are null
https://blog.csdn.net/qq_36458574/article/details/115697287

自己方法：
List<Map<String,Object>> lst = new ArrayList<>();
//SELECT GROUP_CONCAT(distinct p.project_id) proList 
lst = customSqlService.runListSql(sSql);
if(lst.size()>0 && null !=lst.get(0) && null != lst.get(0).get("proList")){
	//这里写代码
}