ABAP Select data from SAP table P20_ATCMP into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP P20_ATCMP 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 P20_ATCMP. 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 P20_ATCMP 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_P20_ATCMP TYPE STANDARD TABLE OF P20_ATCMP,
      WA_P20_ATCMP TYPE P20_ATCMP,
      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: <P20_ATCMP> TYPE P20_ATCMP.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_P20_ATCMP.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM P20_ATCMP
  INTO TABLE IT_P20_ATCMP.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM P20_ATCMP
*  INTO TABLE @DATA(IT_P20_ATCMP2).
*--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_P20_ATCMP INDEX 1 INTO DATA(WA_P20_ATCMP2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_P20_ATCMP ASSIGNING <P20_ATCMP>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<P20_ATCMP>-PAVAL = 1.
<P20_ATCMP>-BUKRS = 1.
<P20_ATCMP>-JUPER = 1.
<P20_ATCMP>-BEGDA = 1.
<P20_ATCMP>-ENDDA = 1.

ENDLOOP.

LOOP AT IT_P20_ATCMP INTO WA_P20_ATCMP.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_P20_ATCMP-BUTXT, sy-vline,
  WA_P20_ATCMP-ORT01, sy-vline,
  WA_P20_ATCMP-LAND1, sy-vline,
  WA_P20_ATCMP-WAERS, sy-vline,
  WA_P20_ATCMP-SPRAS, sy-vline,
  WA_P20_ATCMP-KTOPL, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_P20_ATCMP 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_P20_ATCMP 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_P20_ATCMP INTO WA_P20_ATCMP.


*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 ISOLA, internal->external for field SPRAS
CALL FUNCTION 'CONVERSION_EXIT_ISOLA_OUTPUT'
  EXPORTING
    input =                      WA_P20_ATCMP-SPRAS
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_P20_ATCMP-SPRAS.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field ADRNR
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_P20_ATCMP-ADRNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_P20_ATCMP-ADRNR.
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_P20_ATCMP_STR, 
PAVAL TYPE STRING,
BUKRS TYPE STRING,
JUPER TYPE STRING,
BEGDA TYPE STRING,
ENDDA TYPE STRING,
BUTXT TYPE STRING,
ORT01 TYPE STRING,
LAND1 TYPE STRING,
WAERS TYPE STRING,
SPRAS TYPE STRING,
KTOPL TYPE STRING,
WAABW TYPE STRING,
PERIV TYPE STRING,
FIKRS TYPE STRING,
TXJCD TYPE STRING,
ADRNR TYPE STRING,
STCEG TYPE STRING,
MUNIC TYPE STRING,
ORGBE TYPE STRING,
SONE TYPE STRING,END OF T_EKKO_STR.
DATA: WA_P20_ATCMP_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_P20_ATCMP_STR-PAVAL sy-vline 
WA_P20_ATCMP_STR-BUKRS sy-vline 
WA_P20_ATCMP_STR-JUPER sy-vline 
WA_P20_ATCMP_STR-BEGDA sy-vline 
WA_P20_ATCMP_STR-ENDDA sy-vline 
WA_P20_ATCMP_STR-BUTXT sy-vline 
WA_P20_ATCMP_STR-ORT01 sy-vline 
WA_P20_ATCMP_STR-LAND1 sy-vline 
WA_P20_ATCMP_STR-WAERS sy-vline 
WA_P20_ATCMP_STR-SPRAS sy-vline 
WA_P20_ATCMP_STR-KTOPL sy-vline 
WA_P20_ATCMP_STR-WAABW sy-vline 
WA_P20_ATCMP_STR-PERIV sy-vline 
WA_P20_ATCMP_STR-FIKRS sy-vline 
WA_P20_ATCMP_STR-TXJCD sy-vline 
WA_P20_ATCMP_STR-ADRNR sy-vline 
WA_P20_ATCMP_STR-STCEG sy-vline 
WA_P20_ATCMP_STR-MUNIC sy-vline 
WA_P20_ATCMP_STR-ORGBE sy-vline 
WA_P20_ATCMP_STR-SONE sy-vline      INTO ld_text SEPARATED BY SPACE.

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