title: How to find out which column value changed in SQL
body: <p>I have  two tables with 100 of columns, and I want to find out how which column value changed in those two tables. I can find which row has changed but I want to which column was changed not the whole row. </p>
  
  <pre><code>Table 1 
            name   ID    Dept   Email       EmpID    Salary  Gender  
            Rob     1     IT     I@i.com     100    5000       M 
            Mary    2     HR     M@m.com     20      6000      F 
            Jack    3     IT     J@j.com     30       7000     M 
            Harry   4     Fin     h@h.com    50       5000     M 
            Jay     5     Eng     Null        60       5000    M  
            Ken     6     HR      K@K.com     70       Null    M  
  
   Table 2 
            name   ID    Dept   Email       EmpID   Salary  Gender  
            Rob     1     IT     I@i.com     100    5000       M 
            Mary    2     HR     M@m.com     20      6000      F 
            Jack    3     IT     J@j.com     150     7000     M 
            Harry   4     Fin     h@h.com    50       Null    M 
            Jay     5     Eng     Jy@jy.com  60       5000     M  
            Ken     6     HR      K@K.com    70       6000     M  
  </code></pre>
  
  <p>As we can see Email for Jay existed,  Emp ID for Jack was changed, Salary for Harry is null in Table 2 and Salary was added for Ken. </p>
  
  <p>Expected Output (If this is possible, As I don't want to see all the row values, I just want to see which column value changed, as ID is a unique identifier, I would like to know which ID did  column value change) </p>
  
  <pre><code> ID     columnvaluechanged
    3        EmpID 
    4        Salary 
    5        Email 
    6        Salary 
  </code></pre>