Relation between GL Account and Invoice?

Question

Hi Experts,
I am working with the FI reports for the first time and I do not have any idea on FI functional flow. I have some basic questions like
What is the Relation between GL Account and Invoice?
When will an Invoice be posted into BKPF, BSEG, BSAD, BSID, BSAK and BSIK? Is there any field in these tables which gives the Invoice number against which a GL Account is created?
For example if I want to calculate " no of vendor invoices without PO how can I do that"? How can I know what are vendor invoices created against a PO or without PO?
Thanks for any help in advance and I am bound to reward points.
Sri

Answer 1

<b>What is the Relation between GL Account and Invoice?</b>
SAP's Glossary for GL Account is
"A structure that records value movements in a company code and represents the G/L account items in a chart of accounts.
A G/L account has transaction figures that record changes to the account during a posting period. These figures are totals that are used for G/L reporting."
In accountancy, an account is a label used for recording and reporting a quantity of almost anything. For example when a company pays salary to its staff, They debit Salary account. This is to identify what is the nature of an expense.
An invoice is a message to the buyer of goods or services that contains, among other things, Name of the goods or services, Quantity sent, & Remuneration due.
Invoice is also a SD document used to charge a customer for a delivery of goods or for services rendered.
<b>When will an Invoice be posted into BKPF, BSEG, BSAD, BSID, BSAK and BSIK? Is there any field in these tables which gives the Invoice number against which a GL Account is created?</b>
If it were a vendor invoice. (i.e you purchase items or service and recieve invoice)
Invoice get posted to the tables once someone makes a Logistics Invoice verification through t-code MIRO etc. The teble RBKP gets the first posting.
If it were your own invoice to your customers, then VBAK and VBAP get the posting.  The connectivity of tables are available in http://www.erpgenie.com/abap/tables.htm As far as SAP is concerned an invoice is a document, so you can only trace invoice as a document number, field name is usually BELNR. Even if a vendor invoice arrive, an internal invoice number is generated where the vendor invoice is entered only as a reference field. This is because, each vendor can have inovices of different size and pattern.
<b>How can I know what are vendor invoices created against a PO or without PO?</b>
For a purchase order you can find in table EKBE for BEWTP = Q any invoice document.