ABAP Select data from SAP table MCHI2 into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP MCHI2 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 MCHI2. 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 MCHI2 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_MCHI2 TYPE STANDARD TABLE OF MCHI2,
      WA_MCHI2 TYPE MCHI2,
      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: <MCHI2> TYPE MCHI2.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_MCHI2.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM MCHI2
  INTO TABLE IT_MCHI2.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM MCHI2
*  INTO TABLE @DATA(IT_MCHI22).
*--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_MCHI2 INDEX 1 INTO DATA(WA_MCHI22).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_MCHI2 ASSIGNING <MCHI2>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<MCHI2>-CHAME = 1.
<MCHI2>-LWEDT = 1.
<MCHI2>-FVDT1 = 1.
<MCHI2>-FVDT2 = 1.
<MCHI2>-FVDT3 = 1.

ENDLOOP.

LOOP AT IT_MCHI2 INTO WA_MCHI2.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_MCHI2-FVDT4, sy-vline,
  WA_MCHI2-FVDT5, sy-vline,
  WA_MCHI2-FVDT6, sy-vline,
  WA_MCHI2-HERKL, sy-vline,
  WA_MCHI2-HERKR, sy-vline,
  WA_MCHI2-MTVER, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_MCHI2 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_MCHI2 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_MCHI2 INTO WA_MCHI2.


*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 CUNIT, internal->external for field CHAME
CALL FUNCTION 'CONVERSION_EXIT_CUNIT_OUTPUT'
  EXPORTING
    input =                      WA_MCHI2-CHAME
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MCHI2-CHAME.
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_MCHI2_STR, 
CHAME TYPE STRING,
LWEDT TYPE STRING,
FVDT1 TYPE STRING,
FVDT2 TYPE STRING,
FVDT3 TYPE STRING,
FVDT4 TYPE STRING,
FVDT5 TYPE STRING,
FVDT6 TYPE STRING,
HERKL TYPE STRING,
HERKR TYPE STRING,
MTVER TYPE STRING,
QNDAT TYPE STRING,
HSDAT TYPE STRING,
CUOBJ_BM TYPE STRING,
DEACT_BM TYPE STRING,
BATCH_TYPE TYPE STRING,
SGT_SCAT TYPE STRING,
ERSDA_TMSTP TYPE STRING,
ERSDA_TZ_SYS TYPE STRING,
ERSDA_TZ_USR TYPE STRING,
ZFDAT TYPE STRING,
CREATION_DATETIME TYPE STRING,
LASTCHANGE_DATETIME TYPE STRING,END OF T_EKKO_STR.
DATA: WA_MCHI2_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_MCHI2_STR-CHAME sy-vline 
WA_MCHI2_STR-LWEDT sy-vline 
WA_MCHI2_STR-FVDT1 sy-vline 
WA_MCHI2_STR-FVDT2 sy-vline 
WA_MCHI2_STR-FVDT3 sy-vline 
WA_MCHI2_STR-FVDT4 sy-vline 
WA_MCHI2_STR-FVDT5 sy-vline 
WA_MCHI2_STR-FVDT6 sy-vline 
WA_MCHI2_STR-HERKL sy-vline 
WA_MCHI2_STR-HERKR sy-vline 
WA_MCHI2_STR-MTVER sy-vline 
WA_MCHI2_STR-QNDAT sy-vline 
WA_MCHI2_STR-HSDAT sy-vline 
WA_MCHI2_STR-CUOBJ_BM sy-vline 
WA_MCHI2_STR-DEACT_BM sy-vline 
WA_MCHI2_STR-BATCH_TYPE sy-vline 
WA_MCHI2_STR-SGT_SCAT sy-vline 
WA_MCHI2_STR-ERSDA_TMSTP sy-vline 
WA_MCHI2_STR-ERSDA_TZ_SYS sy-vline 
WA_MCHI2_STR-ERSDA_TZ_USR sy-vline 
WA_MCHI2_STR-ZFDAT sy-vline 
WA_MCHI2_STR-CREATION_DATETIME sy-vline 
WA_MCHI2_STR-LASTCHANGE_DATETIME sy-vline      INTO ld_text SEPARATED BY SPACE.

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