ABAP Select data from SAP table ALSYSTEMS into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM ALSYSTEMS
*  INTO TABLE @DATA(IT_ALSYSTEMS2).
*--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_ALSYSTEMS INDEX 1 INTO DATA(WA_ALSYSTEMS2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<ALSYSTEMS>-SYSID = 1.
<ALSYSTEMS>-DESTINAT = 1.
<ALSYSTEMS>-COMMPRIO = 1.
<ALSYSTEMS>-COMMTYPE = 1.
<ALSYSTEMS>-COMMSTATUS = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_ALSYSTEMS-CS_CHGTMST, sy-vline,
  WA_ALSYSTEMS-CS_CHGCNT, sy-vline,
  WA_ALSYSTEMS-CSMSTATUS, sy-vline,
  WA_ALSYSTEMS-VERSION, sy-vline,
  WA_ALSYSTEMS-CHG_USER, sy-vline,
  WA_ALSYSTEMS-CHG_DATE, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_ALSYSTEMS 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_ALSYSTEMS 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_ALSYSTEMS INTO WA_ALSYSTEMS.


*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_ALSYSTEMS_STR, 
SYSID TYPE STRING,
DESTINAT TYPE STRING,
COMMPRIO TYPE STRING,
COMMTYPE TYPE STRING,
COMMSTATUS TYPE STRING,
CS_CHGTMST TYPE STRING,
CS_CHGCNT TYPE STRING,
CSMSTATUS TYPE STRING,
VERSION TYPE STRING,
CHG_USER TYPE STRING,
CHG_DATE TYPE STRING,
CHG_TIME TYPE STRING,
RESERVE_C TYPE STRING,
RESERVE_I TYPE STRING,
CACHE_TMST TYPE STRING,
DESTINAT_2 TYPE STRING,
NBRSEGM TYPE STRING,
CSMSEGMCMPL TYPE STRING,END OF T_EKKO_STR.
DATA: WA_ALSYSTEMS_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_ALSYSTEMS_STR-SYSID sy-vline 
WA_ALSYSTEMS_STR-DESTINAT sy-vline 
WA_ALSYSTEMS_STR-COMMPRIO sy-vline 
WA_ALSYSTEMS_STR-COMMTYPE sy-vline 
WA_ALSYSTEMS_STR-COMMSTATUS sy-vline 
WA_ALSYSTEMS_STR-CS_CHGTMST sy-vline 
WA_ALSYSTEMS_STR-CS_CHGCNT sy-vline 
WA_ALSYSTEMS_STR-CSMSTATUS sy-vline 
WA_ALSYSTEMS_STR-VERSION sy-vline 
WA_ALSYSTEMS_STR-CHG_USER sy-vline 
WA_ALSYSTEMS_STR-CHG_DATE sy-vline 
WA_ALSYSTEMS_STR-CHG_TIME sy-vline 
WA_ALSYSTEMS_STR-RESERVE_C sy-vline 
WA_ALSYSTEMS_STR-RESERVE_I sy-vline 
WA_ALSYSTEMS_STR-CACHE_TMST sy-vline 
WA_ALSYSTEMS_STR-DESTINAT_2 sy-vline 
WA_ALSYSTEMS_STR-NBRSEGM sy-vline 
WA_ALSYSTEMS_STR-CSMSEGMCMPL sy-vline      INTO ld_text SEPARATED BY SPACE.

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