从结果集中筛选selectsum(total)fromselectcount(*)astotalfromtvistedgroupbyuserid用这句话查询时总是说
从结果集中筛选
select sum(total) from select count(*) as total from tvisted group by userid
用这句话查询时总是说“在关键字 'select ' 附近有语法错误。”不知道为什么
[解决办法]
select sum(total) from
(select count(*) as total from tvisted group by userid)a