ABAP Select data from SAP table P20_ATCRT into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP P20_ATCRT 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_ATCRT. 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_ATCRT 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_ATCRT TYPE STANDARD TABLE OF P20_ATCRT,
      WA_P20_ATCRT TYPE P20_ATCRT,
      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_ATCRT> TYPE P20_ATCRT.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_P20_ATCRT.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM P20_ATCRT
  INTO TABLE IT_P20_ATCRT.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM P20_ATCRT
*  INTO TABLE @DATA(IT_P20_ATCRT2).
*--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_ATCRT INDEX 1 INTO DATA(WA_P20_ATCRT2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_P20_ATCRT ASSIGNING <P20_ATCRT>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<P20_ATCRT>-EMPID = 1.
<P20_ATCRT>-ORGBE = 1.
<P20_ATCRT>-SONE = 1.
<P20_ATCRT>-MUNIC = 1.
<P20_ATCRT>-FYEAR = 1.

ENDLOOP.

LOOP AT IT_P20_ATCRT INTO WA_P20_ATCRT.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_P20_ATCRT-LGART, sy-vline,
  WA_P20_ATCRT-ATGRN, sy-vline,
  WA_P20_ATCRT-ATRNO, sy-vline,
  WA_P20_ATCRT-ATERN, sy-vline,
  WA_P20_ATCRT-KSJOM, sy-vline,
  WA_P20_ATCRT-ENDDA, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_P20_ATCRT 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_ATCRT 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_ATCRT INTO WA_P20_ATCRT.


*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_P20_ATCRT_STR, 
EMPID TYPE STRING,
ORGBE TYPE STRING,
SONE TYPE STRING,
MUNIC TYPE STRING,
FYEAR TYPE STRING,
LGART TYPE STRING,
ATGRN TYPE STRING,
ATRNO TYPE STRING,
ATERN TYPE STRING,
KSJOM TYPE STRING,
ENDDA TYPE STRING,
BEGDA TYPE STRING,
ANZHL TYPE STRING,
BETRG TYPE STRING,
AMT_CURR TYPE STRING,
REIMB TYPE STRING,
PENBASIS TYPE STRING,
LAND1 TYPE STRING,
BOLIG TYPE STRING,
AYEAR TYPE STRING,
FDNUM TYPE STRING,
ADAMT TYPE STRING,
TAXKEY TYPE STRING,
REGNO TYPE STRING,
TOTDR TYPE STRING,
PRVDR TYPE STRING,END OF T_EKKO_STR.
DATA: WA_P20_ATCRT_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_ATCRT_STR-EMPID sy-vline 
WA_P20_ATCRT_STR-ORGBE sy-vline 
WA_P20_ATCRT_STR-SONE sy-vline 
WA_P20_ATCRT_STR-MUNIC sy-vline 
WA_P20_ATCRT_STR-FYEAR sy-vline 
WA_P20_ATCRT_STR-LGART sy-vline 
WA_P20_ATCRT_STR-ATGRN sy-vline 
WA_P20_ATCRT_STR-ATRNO sy-vline 
WA_P20_ATCRT_STR-ATERN sy-vline 
WA_P20_ATCRT_STR-KSJOM sy-vline 
WA_P20_ATCRT_STR-ENDDA sy-vline 
WA_P20_ATCRT_STR-BEGDA sy-vline 
WA_P20_ATCRT_STR-ANZHL sy-vline 
WA_P20_ATCRT_STR-BETRG sy-vline 
WA_P20_ATCRT_STR-AMT_CURR sy-vline 
WA_P20_ATCRT_STR-REIMB sy-vline 
WA_P20_ATCRT_STR-PENBASIS sy-vline 
WA_P20_ATCRT_STR-LAND1 sy-vline 
WA_P20_ATCRT_STR-BOLIG sy-vline 
WA_P20_ATCRT_STR-AYEAR sy-vline 
WA_P20_ATCRT_STR-FDNUM sy-vline 
WA_P20_ATCRT_STR-ADAMT sy-vline 
WA_P20_ATCRT_STR-TAXKEY sy-vline 
WA_P20_ATCRT_STR-REGNO sy-vline 
WA_P20_ATCRT_STR-TOTDR sy-vline 
WA_P20_ATCRT_STR-PRVDR sy-vline      INTO ld_text SEPARATED BY SPACE.

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