ABAP Select data from SAP table /SMB/MCRULE into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP /SMB/MCRULE 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 /SMB/MCRULE. 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 /SMB/MCRULE 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_/SMB/MCRULE TYPE STANDARD TABLE OF /SMB/MCRULE,
      WA_/SMB/MCRULE TYPE /SMB/MCRULE,
      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: </SMB/MCRULE> TYPE /SMB/MCRULE.

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

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM /SMB/MCRULE
  INTO TABLE IT_/SMB/MCRULE.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM /SMB/MCRULE
*  INTO TABLE @DATA(IT_/SMB/MCRULE2).
*--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_/SMB/MCRULE INDEX 1 INTO DATA(WA_/SMB/MCRULE2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_/SMB/MCRULE ASSIGNING </SMB/MCRULE>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
</SMB/MCRULE>-TABNAME = 1.
</SMB/MCRULE>-FIELDNAME = 1.
</SMB/MCRULE>-KEYFLAG = 1.
</SMB/MCRULE>-SOURCE = 1.
</SMB/MCRULE>-GENCHRULE = 1.

ENDLOOP.

LOOP AT IT_/SMB/MCRULE INTO WA_/SMB/MCRULE.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_/SMB/MCRULE-DECISCRIT, sy-vline,
  WA_/SMB/MCRULE-MANCHRULE, sy-vline,
  WA_/SMB/MCRULE-DECCOMMENT, sy-vline,
  WA_/SMB/MCRULE-CHGBYUSER, sy-vline,
  WA_/SMB/MCRULE-TIMESTAMP, sy-vline,
  WA_/SMB/MCRULE-TIMESTAMPRG, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_/SMB/MCRULE 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_/SMB/MCRULE 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_/SMB/MCRULE INTO WA_/SMB/MCRULE.


*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_/SMB/MCRULE_STR, 
TABNAME TYPE STRING,
FIELDNAME TYPE STRING,
KEYFLAG TYPE STRING,
SOURCE TYPE STRING,
GENCHRULE TYPE STRING,
DECISCRIT TYPE STRING,
MANCHRULE TYPE STRING,
DECCOMMENT TYPE STRING,
CHGBYUSER TYPE STRING,
TIMESTAMP TYPE STRING,
TIMESTAMPRG TYPE STRING,END OF T_EKKO_STR.
DATA: WA_/SMB/MCRULE_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_/SMB/MCRULE_STR-TABNAME sy-vline 
WA_/SMB/MCRULE_STR-FIELDNAME sy-vline 
WA_/SMB/MCRULE_STR-KEYFLAG sy-vline 
WA_/SMB/MCRULE_STR-SOURCE sy-vline 
WA_/SMB/MCRULE_STR-GENCHRULE sy-vline 
WA_/SMB/MCRULE_STR-DECISCRIT sy-vline 
WA_/SMB/MCRULE_STR-MANCHRULE sy-vline 
WA_/SMB/MCRULE_STR-DECCOMMENT sy-vline 
WA_/SMB/MCRULE_STR-CHGBYUSER sy-vline 
WA_/SMB/MCRULE_STR-TIMESTAMP sy-vline 
WA_/SMB/MCRULE_STR-TIMESTAMPRG sy-vline      INTO ld_text SEPARATED BY SPACE.

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