--Creating Tables

Create table Ex 
(ID int, 
 EAN int, 
 ASIN BigInt, 
 category NVarchar(20), 
 NAME NVarchar(20), 
 CONDITION NVarchar(20) ) 

Create table Ex1 
(ID int, 
 PRICE Float) 

Create Table Ex2 
(KID int, 
 EAN Int, 
 category NVarchar(20), 
 NAME NVarchar(20), 
 CONDITION NVarchar(20), 
 PRICE Float ) 


--Inserting Sample Data
 
Insert Into Ex 
Select 1, null, 20001, 'ps2', 'COD2', 'new' 
Union ALL
Select 2, 1002, 20002, 'xbox', 'HOLA', 'new'
Union ALL
Select 3, 1003, 20003, 'xbox', 'Spider Man', 'used' 

Insert Into Ex1 
Select 1, 50
Union ALL 
Select 2, 51
Union ALL
Select 3, 61 
 
Insert Into Ex2 
Select 1013, 1001, 'ps2', 'COD2', 'new', 50
Union ALL 
Select 1015, 1002, 'xbox', 'HOLA', 'new', 31 


--Script for your Requirement 

Declare @newKID Int 
Select @newKID = MAX(KID) From Ex2 
IF Exists(Select Name From Ex Except Select Name From Ex2) 
	Begin 
		Insert Into Ex2 
			Select (@newKID + ROW_NUMBER() Over (Order By ID)) As KID, EAN, category, NAME, CONDITION, PRICE From 
				(
					 Select a.Id, a.EAN, a.category, a.NAME, a.CONDITION, b.PRICE  
					 From Ex As a JOIN Ex1 As b ON a.ID = b.ID  
				) As p 
			Where NAME IN (Select Name From Ex Except Select Name From Ex2) 
	End 
IF EXISTS(Select Name From Ex Intersect Select Name From Ex2) 
Begin 
	Update Ex2 
	Set EAN = p.EAN, category = p.category, NAME = p.NAME, CONDITION = p.CONDITION, PRICE = p.PRICE
	From 
	(
		 Select c.EAN, a.category, a.NAME, a.CONDITION, b.PRICE, c.KID 
		 From Ex As a JOIN Ex1 As b ON a.ID = b.ID 
		 JOIN Ex2 As c On a.NAME = c.NAME 
	) As p 
	Where Ex2.EAN = p.EAN
End