ABAP Reports

Reports
There are many different kinds of developments in SAP that are classified as Reports. Common examples include
- Simple reports
- Simple report with drill down functionality
- ALV reports (Basic, grid, hierarchical)
- ALV reports
- Complex ALV reports with drill down, ALV - tree, drag n drop functionalities, etc

Simple Reports –
Easy to develop, usually assigned to beginners, takes about 2-3 days for development based upon complexity
Involves
providing a selection screen for user input,
reading of data from SAP tables using select queries or function modules,
storing the data in internal table and
displaying the contents of internal table as output using WRITE statements

Simple Reports with drill down feature –
Involves capturing user clicks on the report output and achieving a drill down functionality using code written in AT LINE SELECTION
These reports generally make use of sy-lisel (system variable that holds contents of selected line) and HIDE statements to identify the clicked/ selected lines
Formatting of output is done via ABAP command statements such as SY-ULINE, SY-VLINE, FORMAT ON, WRITE with positions, etc.

ALV Reports
ALV stands for ABAP List Viewer
These reports are very much similar to simple ABAP reports with the only difference being the method used for displaying the report output to end user.
These reports make use of standard ALV function modules for displaying the data in tabular format. Unlike simple reports where a lot of formatting is required, ALV handles the formatting and provides a tabular display of report output. It also provides a number of additional functionalities to end user such as sum, sorting, column width adjustment, etc.

Complex ALV Reports –
These involve ALV reports with enhanced features such as
- Drilldown
- Tree display
- Drag n drop feature
These are implemented by using a number of standard methods using OO-ABAP approach.