Question

a. Column Level

GO

CREATE TABLE Products
(
ProductID INT CONSTRAINT pk_products_pid PRIMARY KEY,
ProductName VARCHAR(25)
);

GO

b. Table Level

CREATE TABLE Products
(
ProductID INT,
ProductName VARCHAR(25),
CONSTRAINT pk_products_pid PRIMARY KEY(ProductID)
);
GO 

Is their any difference between Column level and table level constraints?

Answer 1

No. It’s just a matter of personal taste how you apply the constraint.

The primary key constraint is just a primary key constraint – it always applies to the table (after all: it could contain multiple columns – it cannot be “at the column level”).

It’s not “at the column level” once or at the “table level” in the other case – it’s the same always.

Just for fun – you can also create the primary key constraint a third way:

(CREATE TABLE statement)
GO

ALTER TABLE dbo.Products
ADD CONSTRAINT PK_Products_pid PRIMARY KEY(ProductID)

and that again would be identical to the two other options you already have.