Mysql quiz and mysql quiz

Mysql quiz and mysql quiz

1. the user logon log table xes_user_login_logs is as follows:

(1) retrieve user IDs that have been logged on more than twice (SQL statement)

Select user_id from vvt_ceshi group by user_id having (count (user_id)> 1;

HAVING is like the WHERE condition, used to retrieve a dataset according to specified requirements. However, the WHERE clause is generally used to specify conditions for data queries, and HAVING is used to specify conditions for group by grouping.

(2) retrieve the total number of logins that exceeds two (SQL statement)

Select count (sum) from (select count (user_id) as sum from vvt_ceshi group by user_id having (count (user_id)> 1) as B;

2.