ABAP Select data from SAP table GWY_SYSTEM into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM GWY_SYSTEM
*  INTO TABLE @DATA(IT_GWY_SYSTEM2).
*--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_GWY_SYSTEM INDEX 1 INTO DATA(WA_GWY_SYSTEM2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<GWY_SYSTEM>-LUNAME = 1.
<GWY_SYSTEM>-TPNAME = 1.
<GWY_SYSTEM>-CONVID = 1.
<GWY_SYSTEM>-APPCHDR = 1.
<GWY_SYSTEM>-SYSTYPE = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_GWY_SYSTEM-REGSTATE, sy-vline,
  WA_GWY_SYSTEM-ACCPTINFO, sy-vline,
  WA_GWY_SYSTEM-LINE, sy-vline,
  WA_GWY_SYSTEM-HOST1, sy-vline,
  WA_GWY_SYSTEM-ADDR1, sy-vline,
  WA_GWY_SYSTEM-HOST2, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_GWY_SYSTEM 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_GWY_SYSTEM 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_GWY_SYSTEM INTO WA_GWY_SYSTEM.


*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_GWY_SYSTEM_STR, 
LUNAME TYPE STRING,
TPNAME TYPE STRING,
CONVID TYPE STRING,
APPCHDR TYPE STRING,
SYSTYPE TYPE STRING,
REGSTATE TYPE STRING,
ACCPTINFO TYPE STRING,
LINE TYPE STRING,
HOST1 TYPE STRING,
ADDR1 TYPE STRING,
HOST2 TYPE STRING,
ADDR2 TYPE STRING,
HOST3 TYPE STRING,
ADDR3 TYPE STRING,
HOST4 TYPE STRING,
ADDR4 TYPE STRING,
HOST5 TYPE STRING,
ADDR5 TYPE STRING,
LAST_REQ TYPE STRING,
NOCONN TYPE STRING,
FILLER TYPE STRING,END OF T_EKKO_STR.
DATA: WA_GWY_SYSTEM_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_GWY_SYSTEM_STR-LUNAME sy-vline 
WA_GWY_SYSTEM_STR-TPNAME sy-vline 
WA_GWY_SYSTEM_STR-CONVID sy-vline 
WA_GWY_SYSTEM_STR-APPCHDR sy-vline 
WA_GWY_SYSTEM_STR-SYSTYPE sy-vline 
WA_GWY_SYSTEM_STR-REGSTATE sy-vline 
WA_GWY_SYSTEM_STR-ACCPTINFO sy-vline 
WA_GWY_SYSTEM_STR-LINE sy-vline 
WA_GWY_SYSTEM_STR-HOST1 sy-vline 
WA_GWY_SYSTEM_STR-ADDR1 sy-vline 
WA_GWY_SYSTEM_STR-HOST2 sy-vline 
WA_GWY_SYSTEM_STR-ADDR2 sy-vline 
WA_GWY_SYSTEM_STR-HOST3 sy-vline 
WA_GWY_SYSTEM_STR-ADDR3 sy-vline 
WA_GWY_SYSTEM_STR-HOST4 sy-vline 
WA_GWY_SYSTEM_STR-ADDR4 sy-vline 
WA_GWY_SYSTEM_STR-HOST5 sy-vline 
WA_GWY_SYSTEM_STR-ADDR5 sy-vline 
WA_GWY_SYSTEM_STR-LAST_REQ sy-vline 
WA_GWY_SYSTEM_STR-NOCONN sy-vline 
WA_GWY_SYSTEM_STR-FILLER sy-vline      INTO ld_text SEPARATED BY SPACE.

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