CTE MS SQL Query with Joined Update Statement

CTE_Update.sql

		declare @Sku varchar(100) = 'xyz123456'

		;WITH CTE (Sku,StockItemId) AS
		(
			SELECT
				Sku, 
				StockItemId
			FROM 
				table_products
			WHERE
				Sku = @Sku
		)
		
		-- Update Sage Product Images: reset Shopify product ID
		UPDATE 
			ext_si
		SET
			ext_si.field_to_set = null
		FROM 
			table_to_update ext_si
		INNER JOIN
			CTE ON ext_si.StockItemId = CTE.StockItemId