COUNT()函数
COUNT函数用法:COUNT ( [ALL | DISTINCT] column | expression | *)
记录自己的错误:
语句: Right:select (select count(user_id) from Users) Error:select count(select user_id from Users) 错误示例:count()里边不能加查询语句啊!!!
-- select contest_id, round(count(*)/count(se
2024-10-28