MySQL - is there a way to implement a CHECK constraint after creating the table?
Assuming you are using MySQL &gt;= 8.16 when MySQL finally implmemented CHECK constraints, you can do this following: 

ALTER TABLE &lt;table_name&gt;
ADD CHECK (check criteria)


so in your case, it would be 

ALTER TABLE jims_faculty
CHECK (fac_experience &gt;= 2)


If you want to name the constraint, you can do this:

ALTER TABLE jims_faculty
ADD CONSTRAINT chk_fac_experience_gt_2 CHECK (fac_experience &gt;= 2); 


From the manual (incredibly) Prior to MySQL 8.0.16, CREATE TABLE permits only the following limited version of table CHECK constraint syntax, which is parsed and ignored: 

The information in this post was largely gleaned from here.