SELECT

    -- id

    I.ITEMID AS originalId,

    -- relationships

    -- data

    I.NAMEALIAS AS name,
    P.UNITID AS unit,
    P.PRICE AS unitcost,
    P.PRICE AS price

    -- custom value tags --

FROM

	InventTable I
		JOIN InventItemPrice P on I.ITEMID=P.ITEMID

WHERE

	P.MODIFIEDDATETIME = (

	SELECT
		MAX(P2.MODIFIEDDATETIME)
	FROM
		InventItemPrice P2
	WHERE
		P2.ITEMID=I.ITEMID
	)

GROUP BY I.ITEMID, I.NAMEALIAS, P.PRICE, P.UNITID