ABAP Select data from SAP table API_GHCL into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP API_GHCL 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 API_GHCL. 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 API_GHCL 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_API_GHCL TYPE STANDARD TABLE OF API_GHCL,
      WA_API_GHCL TYPE API_GHCL,
      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: <API_GHCL> TYPE API_GHCL.

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM API_GHCL
*  INTO TABLE @DATA(IT_API_GHCL2).
*--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_API_GHCL INDEX 1 INTO DATA(WA_API_GHCL2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<API_GHCL>-STUFE = 1.
<API_GHCL>-MARKI = 1.
<API_GHCL>-UKLAS = 1.
<API_GHCL>-EKLAS = 1.
<API_GHCL>-MKLAS = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_API_GHCL-CLAS1, sy-vline,
  WA_API_GHCL-CLIN1, sy-vline,
  WA_API_GHCL-CLAS2, sy-vline,
  WA_API_GHCL-CLIN2, sy-vline,
  WA_API_GHCL-CLTX1, sy-vline,
  WA_API_GHCL-CLTX2, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_API_GHCL 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_API_GHCL 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_API_GHCL INTO WA_API_GHCL.


*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_API_GHCL_STR, 
STUFE TYPE STRING,
MARKI TYPE STRING,
UKLAS TYPE STRING,
EKLAS TYPE STRING,
MKLAS TYPE STRING,
CLAS1 TYPE STRING,
CLIN1 TYPE STRING,
CLAS2 TYPE STRING,
CLIN2 TYPE STRING,
CLTX1 TYPE STRING,
CLTX2 TYPE STRING,END OF T_EKKO_STR.
DATA: WA_API_GHCL_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_API_GHCL_STR-STUFE sy-vline 
WA_API_GHCL_STR-MARKI sy-vline 
WA_API_GHCL_STR-UKLAS sy-vline 
WA_API_GHCL_STR-EKLAS sy-vline 
WA_API_GHCL_STR-MKLAS sy-vline 
WA_API_GHCL_STR-CLAS1 sy-vline 
WA_API_GHCL_STR-CLIN1 sy-vline 
WA_API_GHCL_STR-CLAS2 sy-vline 
WA_API_GHCL_STR-CLIN2 sy-vline 
WA_API_GHCL_STR-CLTX1 sy-vline 
WA_API_GHCL_STR-CLTX2 sy-vline      INTO ld_text SEPARATED BY SPACE.

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