Postings are made to the goods receipt/invoice receipt (GR/IR) clearing account or to GR/IR accounts whenever goods are delivered and invoice receipts are captured with a material reference.
Postings relating to the same purchase order and purchase order item are updated but not cleared automatically.
To clear open items on GR/IR clearing accounts, you use automatic clearing (transaction F.13 or F.13E). To do this, go to the SAP Easy Access menu and choose Start of the navigation path Accounting Next navigation step Financial Accounting Next navigation step General Ledger Next navigation step Periodic Processing Next navigation step Automatic Clearing End of the navigation path. Here, the program analyzes all open items according to their purchase order number and purchase order item, determines whether they produce a zero balance, and then clears them. Any items that do not produce a zero balance or cannot be assigned to each other remain as open items on the GR/IR clearing account.
通过实务简单讲，sap把收货和发票校验入帐拆分给了两个部门，收货动作就是GR,是由仓库做的存货入帐动作，借存货，贷过渡科目，当收到发票时，财务部门做发票校验入帐动作，借过渡科目，贷应付账款，这样借贷方的过渡就清掉了。
但是由于过渡科目是个虚科目，月末不能在帐上留余额，所以如果当月仓库收货了，而我们没收到发票，那么月末就需要运行暂估程序，把留在系统中的过渡贷方余额转入一个实科目，叫应付账款-暂估，这样我们的试算表就平了；
到了下个月由于这批货物的发票到了需要入帐，系统会借一个过渡科目，但是由于上月底我们把收货的贷方过渡转到了应付账款暂估，没办法对过渡进行清账，所以系统设置了暂估程序次月自动回冲的功能，即当月末把贷方收货过渡转入贷方应付账款暂估后，在次月系统又会将这笔分录自动回冲，使得收货过渡依然留在过渡科目贷方，等待与发票入账产生的借方进行清账。
