ABAP Select data from SAP table J_1GVL_MLBUF into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP J_1GVL_MLBUF 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 J_1GVL_MLBUF. 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 J_1GVL_MLBUF 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_J_1GVL_MLBUF TYPE STANDARD TABLE OF J_1GVL_MLBUF,
      WA_J_1GVL_MLBUF TYPE J_1GVL_MLBUF,
      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: <J_1GVL_MLBUF> TYPE J_1GVL_MLBUF.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_J_1GVL_MLBUF.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM J_1GVL_MLBUF
  INTO TABLE IT_J_1GVL_MLBUF.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM J_1GVL_MLBUF
*  INTO TABLE @DATA(IT_J_1GVL_MLBUF2).
*--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_J_1GVL_MLBUF INDEX 1 INTO DATA(WA_J_1GVL_MLBUF2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_J_1GVL_MLBUF ASSIGNING <J_1GVL_MLBUF>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<J_1GVL_MLBUF>-MANDT = 1.
<J_1GVL_MLBUF>-RELID = 1.
<J_1GVL_MLBUF>-BUKRS = 1.
<J_1GVL_MLBUF>-IASKZ = 1.
<J_1GVL_MLBUF>-DTGRP = 1.

ENDLOOP.

LOOP AT IT_J_1GVL_MLBUF INTO WA_J_1GVL_MLBUF.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_J_1GVL_MLBUF-BUDAT, sy-vline,
  WA_J_1GVL_MLBUF-SRTF2, sy-vline,
  WA_J_1GVL_MLBUF-STROV, sy-vline,
  WA_J_1GVL_MLBUF-CLUSTR, sy-vline,
  WA_J_1GVL_MLBUF-CLUSTD, sy-vline,
ENDLOOP.
   
*Add any further fields from structure WA_J_1GVL_MLBUF 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_J_1GVL_MLBUF 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_J_1GVL_MLBUF INTO WA_J_1GVL_MLBUF.


*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_J_1GVL_MLBUF_STR, 
MANDT TYPE STRING,
RELID TYPE STRING,
BUKRS TYPE STRING,
IASKZ TYPE STRING,
DTGRP TYPE STRING,
BUDAT TYPE STRING,
SRTF2 TYPE STRING,
STROV TYPE STRING,
CLUSTR TYPE STRING,
CLUSTD TYPE STRING,END OF T_EKKO_STR.
DATA: WA_J_1GVL_MLBUF_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_J_1GVL_MLBUF_STR-MANDT sy-vline 
WA_J_1GVL_MLBUF_STR-RELID sy-vline 
WA_J_1GVL_MLBUF_STR-BUKRS sy-vline 
WA_J_1GVL_MLBUF_STR-IASKZ sy-vline 
WA_J_1GVL_MLBUF_STR-DTGRP sy-vline 
WA_J_1GVL_MLBUF_STR-BUDAT sy-vline 
WA_J_1GVL_MLBUF_STR-SRTF2 sy-vline 
WA_J_1GVL_MLBUF_STR-STROV sy-vline 
WA_J_1GVL_MLBUF_STR-CLUSTR sy-vline 
WA_J_1GVL_MLBUF_STR-CLUSTD sy-vline      INTO ld_text SEPARATED BY SPACE.

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