CKI_PDS_ML is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "GR/IR and price diff. posting with standard price control" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_CKI_PDS_ML TYPE CKI_PDS_ML.
The CKI_PDS_ML table consists of various fields, each holding specific information or linking keys about GR/IR and price diff. posting with standard price control data available in SAP. These include PRDIF_1 (Value of price difference posting), PRDIF_2 (Value of price difference posting), PRDIF_3 (Value of price difference posting)... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .