DECLARE @TARIH datetime
SET @TARIH = '20220516'

SELECT 
sth_cari_kodu AS SUPPLIER,
SUM(sth_tutar) AS LAST_3M_PURCHASES,
(SELECT cari_odemeplan_no * -1 FROM CARI_HESAPLAR WHERE cari_kod = sth_cari_kodu) AS PAYMENT_TERM,
(SUM(sth_odeme_op) * -1) / COUNT(*) AS DAYS
FROM STOK_HAREKETLERI 
WHERE sth_evraktip = 3 AND
sth_tarih >= @TARIH - 90 AND sth_tarih <= @TARIH
GROUP BY sth_cari_kodu