как же не умеет? вот рабочий вариант: return await getConnection()
.createQueryBuilder()
.select("cart.cartDocId, COUNT(
cart.id) AS lines, SUM(cart.quantity) as quantity, SUM(cart.summa) as summa")
.from(Cart, 'cart')
.where("cart.uid = :uid", { uid })
.groupBy("cart.cartDocId")
.getRawOne()