ABAP Select data from SAP table P01CST into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP P01CST 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 P01CST. 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 P01CST 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_P01CST TYPE STANDARD TABLE OF P01CST,
      WA_P01CST TYPE P01CST,
      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: <P01CST> TYPE P01CST.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_P01CST.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM P01CST
  INTO TABLE IT_P01CST.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM P01CST
*  INTO TABLE @DATA(IT_P01CST2).
*--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_P01CST INDEX 1 INTO DATA(WA_P01CST2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_P01CST ASSIGNING <P01CST>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<P01CST>-MANDT = 1.
<P01CST>-PERNR = 1.
<P01CST>-STDAT = 1.
<P01CST>-STTYP = 1.
<P01CST>-RNTOP = 1.

ENDLOOP.

LOOP AT IT_P01CST INTO WA_P01CST.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_P01CST-REART, sy-vline,
  WA_P01CST-DTYPE, sy-vline,
  WA_P01CST-SPERR, sy-vline,
  WA_P01CST-STAEN, sy-vline,
  WA_P01CST-STAED, sy-vline,
  WA_P01CST-ZNRAN, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_P01CST 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_P01CST 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_P01CST INTO WA_P01CST.


*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_P01CST_STR, 
MANDT TYPE STRING,
PERNR TYPE STRING,
STDAT TYPE STRING,
STTYP TYPE STRING,
RNTOP TYPE STRING,
REART TYPE STRING,
DTYPE TYPE STRING,
SPERR TYPE STRING,
STAEN TYPE STRING,
STAED TYPE STRING,
ZNRAN TYPE STRING,
WAERS TYPE STRING,END OF T_EKKO_STR.
DATA: WA_P01CST_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_P01CST_STR-MANDT sy-vline 
WA_P01CST_STR-PERNR sy-vline 
WA_P01CST_STR-STDAT sy-vline 
WA_P01CST_STR-STTYP sy-vline 
WA_P01CST_STR-RNTOP sy-vline 
WA_P01CST_STR-REART sy-vline 
WA_P01CST_STR-DTYPE sy-vline 
WA_P01CST_STR-SPERR sy-vline 
WA_P01CST_STR-STAEN sy-vline 
WA_P01CST_STR-STAED sy-vline 
WA_P01CST_STR-ZNRAN sy-vline 
WA_P01CST_STR-WAERS sy-vline      INTO ld_text SEPARATED BY SPACE.

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