ABAP Select data from SAP table T021D into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP T021D 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 T021D. 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 T021D 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_T021D TYPE STANDARD TABLE OF T021D,
      WA_T021D TYPE T021D,
      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: <T021D> TYPE T021D.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_T021D.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM T021D
  INTO TABLE IT_T021D.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM T021D
*  INTO TABLE @DATA(IT_T021D2).
*--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_T021D INDEX 1 INTO DATA(WA_T021D2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_T021D ASSIGNING <T021D>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<T021D>-PROGN = 1.
<T021D>-ANWND = 1.
<T021D>-VARNR = 1.
<T021D>-AKTIV = 1.
<T021D>-ADATE = 1.

ENDLOOP.

LOOP AT IT_T021D INTO WA_T021D.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_T021D-GDATE, sy-vline,
  WA_T021D-GNAME, sy-vline,
  WA_T021D-SAPRL, sy-vline,
  WA_T021D-DYNNR, sy-vline,
  WA_T021D-SYSNAME, sy-vline,
ENDLOOP.
   
*Add any further fields from structure WA_T021D 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_T021D 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_T021D INTO WA_T021D.


*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_T021D_STR, 
PROGN TYPE STRING,
ANWND TYPE STRING,
VARNR TYPE STRING,
AKTIV TYPE STRING,
ADATE TYPE STRING,
GDATE TYPE STRING,
GNAME TYPE STRING,
SAPRL TYPE STRING,
DYNNR TYPE STRING,
SYSNAME TYPE STRING,END OF T_EKKO_STR.
DATA: WA_T021D_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_T021D_STR-PROGN sy-vline 
WA_T021D_STR-ANWND sy-vline 
WA_T021D_STR-VARNR sy-vline 
WA_T021D_STR-AKTIV sy-vline 
WA_T021D_STR-ADATE sy-vline 
WA_T021D_STR-GDATE sy-vline 
WA_T021D_STR-GNAME sy-vline 
WA_T021D_STR-SAPRL sy-vline 
WA_T021D_STR-DYNNR sy-vline 
WA_T021D_STR-SYSNAME sy-vline      INTO ld_text SEPARATED BY SPACE.

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