In this article I am going to explain how we can insert
distinct Column value from one SQL Server table to another SQL Server table
with avoiding delicacy.
Below is my First Table from which I will read distinct
Manager Column value. Like below:
Now see all records in my Employee Table:

Image 1.
Now select Distinct Manager Name from this Table

Image 2.
Below is my Second Table in which I will insert Manager
Name:

Image 3.
Now write your SQL statement to achieve our desired
functionality:
INSERT INTO Manager(ManagerName)
SELECT DISTINCT
ManagerName
FROM Employee
WHERE
ManagerName NOT IN(SELECT ManagerName FROM
Manager);

Image 4.
Now Select Records from manager table:

Image 5.
If you hit this Query again then it will not insert any
duplicate record in Manager records and if a new Manager name comes in Employee
table then it will insert that newly added manager name:

Image 6.