Using ABAP Coding In SAP Standard Query

It is hard to find an easy explanation about ABAP coding in standard queries . In some casesyou can’t easily attach additional information to a field in a Query or you need to call and ABAP function module to do an specific calculation, then adding coding to a local field may be a suitable solution.  To demonstrate this we are going to make a standard query with one table using ABAP Coding on it, instead of creating an infoset with three tables  inner join) as usual.