ABAP Select data from SAP table LCOMS into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM LCOMS
*  INTO TABLE @DATA(IT_LCOMS2).
*--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_LCOMS INDEX 1 INTO DATA(WA_LCOMS2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<LCOMS>-LGNUM = 1.
<LCOMS>-REFNR = 1.
<LCOMS>-RBTYP = 1.
<LCOMS>-DUNKL = 1.
<LCOMS>-FCODE = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_LCOMS-SUBRC, sy-vline,
  WA_LCOMS-SVORB, sy-vline,
  WA_LCOMS-KOMIM, sy-vline,
  WA_LCOMS-EINLM, sy-vline,
  WA_LCOMS-TBELI, sy-vline,
  WA_LCOMS-AUFTE, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_LCOMS 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_LCOMS 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_LCOMS INTO WA_LCOMS.


*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.

*Conversion exit ALPHA, internal->external for field REFNR
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_LCOMS-REFNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_LCOMS-REFNR.
WRITE:/ 'New Value:', ld_input.
ENDFORM. 

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

TYPES: BEGIN OF T_LCOMS_STR, 
LGNUM TYPE STRING,
REFNR TYPE STRING,
RBTYP TYPE STRING,
DUNKL TYPE STRING,
FCODE TYPE STRING,
SUBRC TYPE STRING,
SVORB TYPE STRING,
KOMIM TYPE STRING,
EINLM TYPE STRING,
TBELI TYPE STRING,
AUFTE TYPE STRING,
DIREK TYPE STRING,END OF T_EKKO_STR.
DATA: WA_LCOMS_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_LCOMS_STR-LGNUM sy-vline 
WA_LCOMS_STR-REFNR sy-vline 
WA_LCOMS_STR-RBTYP sy-vline 
WA_LCOMS_STR-DUNKL sy-vline 
WA_LCOMS_STR-FCODE sy-vline 
WA_LCOMS_STR-SUBRC sy-vline 
WA_LCOMS_STR-SVORB sy-vline 
WA_LCOMS_STR-KOMIM sy-vline 
WA_LCOMS_STR-EINLM sy-vline 
WA_LCOMS_STR-TBELI sy-vline 
WA_LCOMS_STR-AUFTE sy-vline 
WA_LCOMS_STR-DIREK sy-vline      INTO ld_text SEPARATED BY SPACE.

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