+# all invoice entries of an example part:
+
+# id | trans_id | base_qty | allocated | sellprice | inventory_accno | income_accno | expense_accno
+# ---+----------+----------+-----------+-----------+-----------------+--------------+---------------
+# 4 | 4 | -5 | 5 | 20.00000 | 1140 | 4400 | 5400 bought 5 for 20
+# 5 | 5 | 4 | -4 | 50.00000 | 1140 | 4400 | 5400 sold 4 for 50
+# 6 | 6 | 1 | -1 | 50.00000 | 1140 | 4400 | 5400 sold 1 for 50
+# 7 | 7 | -5 | 1 | 20.00000 | 1140 | 4400 | 5400 bought 5 for 20
+# 8 | 8 | 1 | -1 | 50.00000 | 1140 | 4400 | 5400 sold 1 for 50
+
+# AND ((i.base_qty + i.allocated) < 0) filters out all but line with id=7, elsewhere i.base_qty + i.allocated has already reached 0
+# and all parts have been allocated
+
+# so transaction 8 only sees transaction 7 with unallocated parts and adjusts allocated for that transaction, before allocated was 0
+# 7 | 7 | -5 | 1 | 20.00000 | 1140 | 4400 | 5400 bought 5 for 20
+
+# in this example there are still 4 unsold articles
+
+
+ # search all invoice entries for the part in question, adjusting "allocated"
+ # until the total number of sold parts has been reached
+
+ # ORDER BY trans_id ensures FIFO
+
+