Mysql – How to generate missing values for each employee for each day

CREATE TABLE `EmpWorkCount` (
      `emp_Id` int(10) unsigned NOT NULL AUTO_INCREMENT,
      `day` int(10) unsigned NOT NUL,
      `created_At` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
      `updated_At` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
      `daycount` int(10) NOT NULL DEFAULT '0',
    ) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci

Current Values in the table :

    emp_Id    |       day            | daycount  |
       1      |        0             |  10       |
       1      |        1             |  11       | 
       2      |        1             |  13       | 
       2      |        0             |  12       | 

.

CREATE TABLE `Emp` (
      `emp_Id` int(10) unsigned NOT NULL AUTO_INCREMENT,
      `created_At` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
      `updated_At` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
    ) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci

Emp Table looks like :

emp_Id    |       created_At            | updated_At            |
   1      |        2018-12-04 20:00:00  |  2018-12-04 20:00:00  |
   1      |        2018-12-04 20:00:00  |  2018-12-04 20:00:00  | 
   3      |        2018-12-04 20:00:00  |  2018-12-04 20:00:00  |

I need to run a query where I need a count of EmpWorkCount with different day values (0, 1, 2, 3) for each employee

    Select emp_Id, day_list.day, 
    IF(daycount = NULL, 0, daycount)  as daycount from (
        SELECT 0 day
           UNION ALL
           SELECT 1
           UNION ALL
           SELECT 2
           UNION ALL
           SELECT 3   )day_list 
      LEFT JOIN 
      select emp_Id, day, daycount from EmpWorkCount
   )   

(my query is incorrect, but I don't know how I multiply these 4 values from day for each employee

this gives output for the emp_Id, day values present in the table e.g.

emp_Id    |       day            | daycount    |
   1      |        0             |  10         |
   1      |        1             |  11         | 
   2      |        1             |  13         |
   2      |        0             |  12         | 
   NULL   |        2             |  0          | 
   NULL   |        3             |  0          | 

but if the database does not contain let's say emp_Id : 1 with day values = 2 or 3 these records don't appear with a count 0.

Output that I look for :

    emp_Id    |       day            | daycount    |
       1      |        0             |  10         |
       1      |        1             |  11         | 
       1      |        2             |  0          |
       1      |        3             |  0          | 
       2      |        1             |  13         |
       2      |        0             |  12         | 
       2      |        2             |  0          | 
       2      |        3             |  0          | 
       3      |        0             |  0          |
       3      |        1             |  0          | 
       3      |        2             |  0          | 
       3      |        3             |  0          | 

How do I go about this one?

In my query I have not joined with Employee Table –> but the output should even contain Employees which do not have a entry in EmpWorkCount Table.