ALV

                 Sap provides a set of ALV (ABAP LIST VIEWER) function modules, which can be put into use to embellish the output of a report. This set of ALV functions is used to enhance the readability and functionality of any report output. Cases arise in sap when the output of a report contains columns extending more than 255 characters in length.  In such cases, this set of ALV functions can help choose selected columns and arrange the different columns from a report output and also save different variants for report display. This is a very efficient tool for dynamically sorting and arranging the columns from a report output. 

          The report output can contain up to 90 columns in the display with the wide array of display options.

 
The commonly used ALV functions used for this purpose are;
Reuse_alv_fieldcatalog_merge :- It can built automatically the field      

                                                                   catalog needed in ALV list functions.
Reuse_alv_list_display            :- This FM is Used To Display ALV Hierarchy
Reuse_alv_events_get            :- This FM is used to get the default event      
                                                table of the ALV LIST DISPLAY.
Reuse_alv_grid_display           :- This Fm is used To display ALV in Grid           
                                                 Format
Reuse_alv_commentary_write  :- This Fm is used To Display Top of page &    
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