ABAP Select data from SAP table LAW2D_USMM_SYST into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP LAW2D_USMM_SYST 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 LAW2D_USMM_SYST. 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 LAW2D_USMM_SYST 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_LAW2D_USMM_SYST TYPE STANDARD TABLE OF LAW2D_USMM_SYST,
      WA_LAW2D_USMM_SYST TYPE LAW2D_USMM_SYST,
      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: <LAW2D_USMM_SYST> TYPE LAW2D_USMM_SYST.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_LAW2D_USMM_SYST.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM LAW2D_USMM_SYST
  INTO TABLE IT_LAW2D_USMM_SYST.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM LAW2D_USMM_SYST
*  INTO TABLE @DATA(IT_LAW2D_USMM_SYST2).
*--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_LAW2D_USMM_SYST INDEX 1 INTO DATA(WA_LAW2D_USMM_SYST2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_LAW2D_USMM_SYST ASSIGNING <LAW2D_USMM_SYST>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<LAW2D_USMM_SYST>-MANDT = 1.
<LAW2D_USMM_SYST>-DATASETGUID = 1.
<LAW2D_USMM_SYST>-SYSTEMGUID = 1.
<LAW2D_USMM_SYST>-SYSTEMNO = 1.
<LAW2D_USMM_SYST>-SYSID = 1.

ENDLOOP.

LOOP AT IT_LAW2D_USMM_SYST INTO WA_LAW2D_USMM_SYST.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_LAW2D_USMM_SYST-INSTNO, sy-vline,
  WA_LAW2D_USMM_SYST-HWKEY, sy-vline,
  WA_LAW2D_USMM_SYST-USEDDATABASE, sy-vline,
  WA_LAW2D_USMM_SYST-SAPRELEASE, sy-vline,
  WA_LAW2D_USMM_SYST-PRICELIST, sy-vline,
  WA_LAW2D_USMM_SYST-RESULTDATE, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_LAW2D_USMM_SYST 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_LAW2D_USMM_SYST 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_LAW2D_USMM_SYST INTO WA_LAW2D_USMM_SYST.


*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_LAW2D_USMM_SYST_STR, 
MANDT TYPE STRING,
DATASETGUID TYPE STRING,
SYSTEMGUID TYPE STRING,
SYSTEMNO TYPE STRING,
SYSID TYPE STRING,
INSTNO TYPE STRING,
HWKEY TYPE STRING,
USEDDATABASE TYPE STRING,
SAPRELEASE TYPE STRING,
PRICELIST TYPE STRING,
RESULTDATE TYPE STRING,
STATUS TYPE STRING,
SYSSTATUS TYPE STRING,
MEASSTATUS TYPE STRING,
MEASUSER TYPE STRING,
MEASDATE TYPE STRING,
MEASTIME TYPE STRING,
EXTSYSTEMFLAG TYPE STRING,
EXTSYSTEMID TYPE STRING,END OF T_EKKO_STR.
DATA: WA_LAW2D_USMM_SYST_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_LAW2D_USMM_SYST_STR-MANDT sy-vline 
WA_LAW2D_USMM_SYST_STR-DATASETGUID sy-vline 
WA_LAW2D_USMM_SYST_STR-SYSTEMGUID sy-vline 
WA_LAW2D_USMM_SYST_STR-SYSTEMNO sy-vline 
WA_LAW2D_USMM_SYST_STR-SYSID sy-vline 
WA_LAW2D_USMM_SYST_STR-INSTNO sy-vline 
WA_LAW2D_USMM_SYST_STR-HWKEY sy-vline 
WA_LAW2D_USMM_SYST_STR-USEDDATABASE sy-vline 
WA_LAW2D_USMM_SYST_STR-SAPRELEASE sy-vline 
WA_LAW2D_USMM_SYST_STR-PRICELIST sy-vline 
WA_LAW2D_USMM_SYST_STR-RESULTDATE sy-vline 
WA_LAW2D_USMM_SYST_STR-STATUS sy-vline 
WA_LAW2D_USMM_SYST_STR-SYSSTATUS sy-vline 
WA_LAW2D_USMM_SYST_STR-MEASSTATUS sy-vline 
WA_LAW2D_USMM_SYST_STR-MEASUSER sy-vline 
WA_LAW2D_USMM_SYST_STR-MEASDATE sy-vline 
WA_LAW2D_USMM_SYST_STR-MEASTIME sy-vline 
WA_LAW2D_USMM_SYST_STR-EXTSYSTEMFLAG sy-vline 
WA_LAW2D_USMM_SYST_STR-EXTSYSTEMID sy-vline      INTO ld_text SEPARATED BY SPACE.

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