ABAP Select data from SAP table WSTN_AL_LINK into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM WSTN_AL_LINK
*  INTO TABLE @DATA(IT_WSTN_AL_LINK2).
*--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_WSTN_AL_LINK INDEX 1 INTO DATA(WA_WSTN_AL_LINK2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<WSTN_AL_LINK>-MANDT = 1.
<WSTN_AL_LINK>-STYLNR = 1.
<WSTN_AL_LINK>-SAISJ = 1.
<WSTN_AL_LINK>-SAISO = 1.
<WSTN_AL_LINK>-SAITY = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_WSTN_AL_LINK-ABELN, sy-vline,
  WA_WSTN_AL_LINK-AUFAR, sy-vline,
  WA_WSTN_AL_LINK-EKORG, sy-vline,
  WA_WSTN_AL_LINK-EKGRP, sy-vline,
  WA_WSTN_AL_LINK-LIFNR, sy-vline,
  WA_WSTN_AL_LINK-ADD_DC_PO, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_WSTN_AL_LINK 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_WSTN_AL_LINK 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_WSTN_AL_LINK INTO WA_WSTN_AL_LINK.


*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 MATN1, internal->external for field STYLNR
CALL FUNCTION 'CONVERSION_EXIT_MATN1_OUTPUT'
  EXPORTING
    input =                      WA_WSTN_AL_LINK-STYLNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_WSTN_AL_LINK-STYLNR.
WRITE:/ 'New Value:', ld_input.

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

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

*Conversion exit ALPHA, internal->external for field LIFNR
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_WSTN_AL_LINK-LIFNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_WSTN_AL_LINK-LIFNR.
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_WSTN_AL_LINK_STR, 
MANDT TYPE STRING,
STYLNR TYPE STRING,
SAISJ TYPE STRING,
SAISO TYPE STRING,
SAITY TYPE STRING,
ABELN TYPE STRING,
AUFAR TYPE STRING,
EKORG TYPE STRING,
EKGRP TYPE STRING,
LIFNR TYPE STRING,
ADD_DC_PO TYPE STRING,
PLANNR TYPE STRING,END OF T_EKKO_STR.
DATA: WA_WSTN_AL_LINK_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_WSTN_AL_LINK_STR-MANDT sy-vline 
WA_WSTN_AL_LINK_STR-STYLNR sy-vline 
WA_WSTN_AL_LINK_STR-SAISJ sy-vline 
WA_WSTN_AL_LINK_STR-SAISO sy-vline 
WA_WSTN_AL_LINK_STR-SAITY sy-vline 
WA_WSTN_AL_LINK_STR-ABELN sy-vline 
WA_WSTN_AL_LINK_STR-AUFAR sy-vline 
WA_WSTN_AL_LINK_STR-EKORG sy-vline 
WA_WSTN_AL_LINK_STR-EKGRP sy-vline 
WA_WSTN_AL_LINK_STR-LIFNR sy-vline 
WA_WSTN_AL_LINK_STR-ADD_DC_PO sy-vline 
WA_WSTN_AL_LINK_STR-PLANNR sy-vline      INTO ld_text SEPARATED BY SPACE.

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