i have 2 tables EmployeeData and employeePersonalData.
I have common column emailId. 
Now I want copy all the emailId from employeeData to employeePersonalData
how can I do?
i have 2 tables EmployeeData and employeePersonalData.
I have common column emailId. 
Now I want copy all the emailId from employeeData to employeePersonalData
how can I do?
 
    
    you can visit similar question
It provides us two approach.
Before that please check you should be having one more common column similar to EmployeeId in both the tables. 
so then you can use either of below approach -
1) using UPDATE FROM with a JOIN will help
Update employeePersonalData 
   set employeePersonalData.emailId =employeeData.emailId 
  from employeePersonalData  inner join employeeData b 
    on employeePersonalData.emploeeId =employeeData.employeeId
2) Using merge 
MERGE INTO employeePersonalData
   USING employeeData
      ON employeePersonalData.emailId =employeeData.emailId 
WHEN MATCHED THEN
   UPDATE 
      SET employeePersonalData.emailId =employeeData.emailId;
 
    
     
    
    Update a set a.emailId =b.emailId from employeePersonalData a inner join employeeData b on a.emailId =b.emailId
