ABAP Select data from SAP table GGAEL into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP GGAEL table and store it within an internal table, including using the newer @DATA inline declaration methods. It also shows you various ways to process this data using ABAP work area, inline declaration or field symbols including executing all the relevant CONVERSION_EXIT routines specific to GGAEL. See here for more generic Select statement tips.

Sometimes data within SAP is stored within the database table in a different format to what it is displayed to the user. These input/output conversation FM routines are what translates the data between the two formats.

There is also a full declaration of the GGAEL table where each field has a char/string type for you to simply copy and paste. This allows you to use processing that is only available to these field types such as the CONCATENATE statement.

DATA: IT_GGAEL TYPE STANDARD TABLE OF GGAEL,
      WA_GGAEL TYPE GGAEL,
      GD_STR TYPE STRING.

DATA: lo_typedescr type REF TO cl_abap_typedescr.
DATA: lv_fieldname type fieldname.

FIELD-SYMBOLS: <FIELD> TYPE any.
FIELD-SYMBOLS: <GGAEL> TYPE GGAEL.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_GGAEL.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM GGAEL
  INTO TABLE IT_GGAEL.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM GGAEL
*  INTO TABLE @DATA(IT_GGAEL2).
*--Further methods of using ABAP code to  select data from SAP database tables

*You can also declare the header/work area using the in-line DATA declaration method
READ TABLE IT_GGAEL INDEX 1 INTO DATA(WA_GGAEL2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_GGAEL ASSIGNING <GGAEL>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<GGAEL>-ITEMNO = 1.
<GGAEL>-EL_ID = 1.
<GGAEL>-BEG = 1.
<GGAEL>-DUR = 1.
<GGAEL>-TXT = 1.

ENDLOOP.

LOOP AT IT_GGAEL INTO WA_GGAEL.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_GGAEL-PLACE, sy-vline,
  WA_GGAEL-HEIGH, sy-vline,
  WA_GGAEL-PATTR, sy-vline,
  WA_GGAEL-BAKGR, sy-vline,
  WA_GGAEL-FORGR, sy-vline,
  WA_GGAEL-BORDR, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_GGAEL you want to display...

  WRITE:/ sy-uline.
* Aternatively use generic code to Write field values (and NAME) to screen report
  DO.
    ASSIGN COMPONENT sy-index OF STRUCTURE wa_GGAEL TO <field>.
    IF sy-subrc <> 0. EXIT. ENDIF.
    WRITE:/ 'Field Value', <field>, sy-vline.
    gd_str = <field> .
    lo_typedescr ?= CL_ABAP_DATADESCR=>DESCRIBE_BY_DATA( <field> ).
    lv_fieldname = lo_typedescr->GET_RELATIVE_NAME( ).
    WRITE:/ 'Field Name', lv_fieldname.
  ENDDO.

  
*Redo loop but convert all fields from internal to out value  
LOOP AT IT_GGAEL INTO WA_GGAEL.


*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Convert all fields to display/output versions using conversion routines
  PERFORM convert_all_field_values CHANGING wa_EKKO.
	 
ENDLOOP.

  
*&---------------------------------------------------------------------*
*& Form convert_all_field_values
*&---------------------------------------------------------------------*
FORM convert_all_field_values CHANGING p_EKKO LIKE wa_EKKO.
DATA: ld_input(1000) TYPE c, ld_output(1000) TYPE C.
ENDFORM. 

*&---------------------------------------------------------------------*
*& Form process_as_string_field_values
*&---------------------------------------------------------------------*
FORM process_as_string_field_values CHANGING p_EKKO LIKE wa_EKKO.

TYPES: BEGIN OF T_GGAEL_STR, 
ITEMNO TYPE STRING,
EL_ID TYPE STRING,
BEG TYPE STRING,
DUR TYPE STRING,
TXT TYPE STRING,
PLACE TYPE STRING,
HEIGH TYPE STRING,
PATTR TYPE STRING,
BAKGR TYPE STRING,
FORGR TYPE STRING,
BORDR TYPE STRING,
BRDON TYPE STRING,
FILLD TYPE STRING,END OF T_EKKO_STR.
DATA: WA_GGAEL_STR type T_EKKO_STR.

DATA: ld_text TYPE string.

LOOP AT IT_EKKO INTO WA_EKKO.
  MOVE-CORRESPONDING wa_EKKO TO WA_EKKO_STR.
  CONCATENATE: sy-vline
WA_GGAEL_STR-ITEMNO sy-vline 
WA_GGAEL_STR-EL_ID sy-vline 
WA_GGAEL_STR-BEG sy-vline 
WA_GGAEL_STR-DUR sy-vline 
WA_GGAEL_STR-TXT sy-vline 
WA_GGAEL_STR-PLACE sy-vline 
WA_GGAEL_STR-HEIGH sy-vline 
WA_GGAEL_STR-PATTR sy-vline 
WA_GGAEL_STR-BAKGR sy-vline 
WA_GGAEL_STR-FORGR sy-vline 
WA_GGAEL_STR-BORDR sy-vline 
WA_GGAEL_STR-BRDON sy-vline 
WA_GGAEL_STR-FILLD sy-vline      INTO ld_text SEPARATED BY SPACE.

*Add any further fields from structure WA_EKKO_STR you want to CONCATENATE...
ENDLOOP.
ENDFORM.