What to do if Linux Mint won't start?

Question

mint

I installed Linux Mint (The computer is also running Windows). For a while, everything started well and worked. Once I wanted to run Linux Mint. I enter my username and password and press the button to enter the system. After a short time, the screen goes dark and asks you to log in again. If I enter the wrong password, then immediately writes that the password is wrong, so the password is correct. What to do?
PS In guest mode it starts.

Answer 1

create a new account, from under it you will deal with the old one,
you can also from under the root, but in order not to screw up completely, it’s
better to create another user account, give it admin rights so that you can fix the second one,
and then ,
as an option, just transfer the configs from one hamster to another,
but not all at once, but in parts / thoughtfully,
then you will understand what problems you had there

Answer 2

one.

SELECT w.*, 
        t.name as trainer_name,
        c.name as client_name
FROM workout w
INNER JOIN trainers t ON t.id = w.trainer
INNER JOIN clients c ON c.id = w.client
WHERE w.day = DAYOFMONTH(NOW())
    AND w.month = MONTH(NOW())
    AND w.year = YEAR(NOW())

2. Lynch the programmer who came up with the structure for the first table.
3. Remove all date fields. Add two new ones: "Date From" and "Date To", both datetime.

Answer 3

I think you need to read the documentation first .

Answer 4

I understand that you display the date as "the day when the black cat crossed my path, the month of the return of the cranes from the south, the third year of the Qin dynasty." Otherwise, it is not clear why the standard DATE type was not used and why the tables `days`, `months`, `years` are needed. There is also a standard field for time - TIME, there is no need to store it in VARCHAR.
And joining tables - LEFT JOIN

SELECT `w`.`gym`, `t`.`name`, `c`.`name`, `w`.`sttime`, `w`.`entime`
    FROM `workout` AS `w`
    LEFT JOIN `trainers` AS `t` ON `t`.`id` = `w`.`trainer`
    LEFT JOIN `clients` AS `c` ON `c`.`id` = `w`.`client`
    WHERE `w`.`date` = CURDATE()
    ORDER BY `w`.`sttime`