ABAP Select data from SAP table OIA_NESTHD into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM OIA_NESTHD
*  INTO TABLE @DATA(IT_OIA_NESTHD2).
*--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_OIA_NESTHD INDEX 1 INTO DATA(WA_OIA_NESTHD2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<OIA_NESTHD>-BUKRS = 1.
<OIA_NESTHD>-NETNUM = 1.
<OIA_NESTHD>-NJAHR = 1.
<OIA_NESTHD>-NETCYC = 1.
<OIA_NESTHD>-TEXTL = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_OIA_NESTHD-BLDAT, sy-vline,
  WA_OIA_NESTHD-ERDAT, sy-vline,
  WA_OIA_NESTHD-ERNAM, sy-vline,
  WA_OIA_NESTHD-EXGPTR, sy-vline,
  WA_OIA_NESTHD-LIFNR, sy-vline,
  WA_OIA_NESTHD-KUNNR, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_OIA_NESTHD 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_OIA_NESTHD 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_OIA_NESTHD INTO WA_OIA_NESTHD.


*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 GJAHR, internal->external for field NJAHR
CALL FUNCTION 'CONVERSION_EXIT_GJAHR_OUTPUT'
  EXPORTING
    input =                      WA_OIA_NESTHD-NJAHR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_OIA_NESTHD-NJAHR.
WRITE:/ 'New Value:', ld_input.

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

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

*Conversion exit ALPHA, internal->external for field KUNNR
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_OIA_NESTHD-KUNNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_OIA_NESTHD-KUNNR.
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_OIA_NESTHD_STR, 
BUKRS TYPE STRING,
NETNUM TYPE STRING,
NJAHR TYPE STRING,
NETCYC TYPE STRING,
TEXTL TYPE STRING,
BLDAT TYPE STRING,
ERDAT TYPE STRING,
ERNAM TYPE STRING,
EXGPTR TYPE STRING,
LIFNR TYPE STRING,
KUNNR TYPE STRING,
ANRED TYPE STRING,
NAME1 TYPE STRING,
NAME2 TYPE STRING,
NAME3 TYPE STRING,
NAME4 TYPE STRING,
STRAS TYPE STRING,
PFACH TYPE STRING,
PFORT TYPE STRING,
PSTL2 TYPE STRING,
LAND1 TYPE STRING,
PSTLZ TYPE STRING,
ORT01 TYPE STRING,
ORT02 TYPE STRING,
REGIO TYPE STRING,
SLAND TYPE STRING,
RECEIVABLE TYPE STRING,
PAYABLE TYPE STRING,
BALANCE TYPE STRING,
WAERS TYPE STRING,END OF T_EKKO_STR.
DATA: WA_OIA_NESTHD_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_OIA_NESTHD_STR-BUKRS sy-vline 
WA_OIA_NESTHD_STR-NETNUM sy-vline 
WA_OIA_NESTHD_STR-NJAHR sy-vline 
WA_OIA_NESTHD_STR-NETCYC sy-vline 
WA_OIA_NESTHD_STR-TEXTL sy-vline 
WA_OIA_NESTHD_STR-BLDAT sy-vline 
WA_OIA_NESTHD_STR-ERDAT sy-vline 
WA_OIA_NESTHD_STR-ERNAM sy-vline 
WA_OIA_NESTHD_STR-EXGPTR sy-vline 
WA_OIA_NESTHD_STR-LIFNR sy-vline 
WA_OIA_NESTHD_STR-KUNNR sy-vline 
WA_OIA_NESTHD_STR-ANRED sy-vline 
WA_OIA_NESTHD_STR-NAME1 sy-vline 
WA_OIA_NESTHD_STR-NAME2 sy-vline 
WA_OIA_NESTHD_STR-NAME3 sy-vline 
WA_OIA_NESTHD_STR-NAME4 sy-vline 
WA_OIA_NESTHD_STR-STRAS sy-vline 
WA_OIA_NESTHD_STR-PFACH sy-vline 
WA_OIA_NESTHD_STR-PFORT sy-vline 
WA_OIA_NESTHD_STR-PSTL2 sy-vline 
WA_OIA_NESTHD_STR-LAND1 sy-vline 
WA_OIA_NESTHD_STR-PSTLZ sy-vline 
WA_OIA_NESTHD_STR-ORT01 sy-vline 
WA_OIA_NESTHD_STR-ORT02 sy-vline 
WA_OIA_NESTHD_STR-REGIO sy-vline 
WA_OIA_NESTHD_STR-SLAND sy-vline 
WA_OIA_NESTHD_STR-RECEIVABLE sy-vline 
WA_OIA_NESTHD_STR-PAYABLE sy-vline 
WA_OIA_NESTHD_STR-BALANCE sy-vline 
WA_OIA_NESTHD_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.