ABAP Select data from SAP table MDAT1 into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP MDAT1 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 MDAT1. 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 MDAT1 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_MDAT1 TYPE STANDARD TABLE OF MDAT1,
      WA_MDAT1 TYPE MDAT1,
      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: <MDAT1> TYPE MDAT1.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_MDAT1.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM MDAT1
  INTO TABLE IT_MDAT1.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM MDAT1
*  INTO TABLE @DATA(IT_MDAT12).
*--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_MDAT1 INDEX 1 INTO DATA(WA_MDAT12).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_MDAT1 ASSIGNING <MDAT1>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<MDAT1>-MAX_COMM = 1.
<MDAT1>-MESSLEVEL = 1.
<MDAT1>-SPERA = 1.
<MDAT1>-N_EING_F = 1.
<MDAT1>-KZ_VERW = 1.

ENDLOOP.

LOOP AT IT_MDAT1 INTO WA_MDAT1.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_MDAT1-KZ_AEND, sy-vline,
  WA_MDAT1-KZ_DISPO, sy-vline,
  WA_MDAT1-KZ_MUSS, sy-vline,
  WA_MDAT1-KZ_TEST, sy-vline,
  WA_MDAT1-KZ_RONLY, sy-vline,
  WA_MDAT1-KZ_NUMV, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_MDAT1 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_MDAT1 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_MDAT1 INTO WA_MDAT1.


*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_MDAT1_STR, 
MAX_COMM TYPE STRING,
MESSLEVEL TYPE STRING,
SPERA TYPE STRING,
N_EING_F TYPE STRING,
KZ_VERW TYPE STRING,
KZ_AEND TYPE STRING,
KZ_DISPO TYPE STRING,
KZ_MUSS TYPE STRING,
KZ_TEST TYPE STRING,
KZ_RONLY TYPE STRING,
KZ_NUMV TYPE STRING,
KZ_PSTA TYPE STRING,
ERFMELD TYPE STRING,
MAX_ERR TYPE STRING,END OF T_EKKO_STR.
DATA: WA_MDAT1_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_MDAT1_STR-MAX_COMM sy-vline 
WA_MDAT1_STR-MESSLEVEL sy-vline 
WA_MDAT1_STR-SPERA sy-vline 
WA_MDAT1_STR-N_EING_F sy-vline 
WA_MDAT1_STR-KZ_VERW sy-vline 
WA_MDAT1_STR-KZ_AEND sy-vline 
WA_MDAT1_STR-KZ_DISPO sy-vline 
WA_MDAT1_STR-KZ_MUSS sy-vline 
WA_MDAT1_STR-KZ_TEST sy-vline 
WA_MDAT1_STR-KZ_RONLY sy-vline 
WA_MDAT1_STR-KZ_NUMV sy-vline 
WA_MDAT1_STR-KZ_PSTA sy-vline 
WA_MDAT1_STR-ERFMELD sy-vline 
WA_MDAT1_STR-MAX_ERR sy-vline      INTO ld_text SEPARATED BY SPACE.

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