ABAP Select data from SAP table MWLI_DAT into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM MWLI_DAT
*  INTO TABLE @DATA(IT_MWLI_DAT2).
*--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_MWLI_DAT INDEX 1 INTO DATA(WA_MWLI_DAT2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<MWLI_DAT>-SSTUF = 1.
<MWLI_DAT>-PFLKS = 1.
<MWLI_DAT>-LSTFL = 1.
<MWLI_DAT>-LSTVZ = 1.
<MWLI_DAT>-LSTAK = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_MWLI_DAT-LDVFL, sy-vline,
  WA_MWLI_DAT-LDBFL, sy-vline,
  WA_MWLI_DAT-LDVZL, sy-vline,
  WA_MWLI_DAT-LDBZL, sy-vline,
  WA_MWLI_DAT-VDVFL, sy-vline,
  WA_MWLI_DAT-VDBFL, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_MWLI_DAT 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_MWLI_DAT 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_MWLI_DAT INTO WA_MWLI_DAT.


*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_MWLI_DAT_STR, 
SSTUF TYPE STRING,
PFLKS TYPE STRING,
LSTFL TYPE STRING,
LSTVZ TYPE STRING,
LSTAK TYPE STRING,
LDVFL TYPE STRING,
LDBFL TYPE STRING,
LDVZL TYPE STRING,
LDBZL TYPE STRING,
VDVFL TYPE STRING,
VDBFL TYPE STRING,
VDVZL TYPE STRING,
VDBZL TYPE STRING,END OF T_EKKO_STR.
DATA: WA_MWLI_DAT_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_MWLI_DAT_STR-SSTUF sy-vline 
WA_MWLI_DAT_STR-PFLKS sy-vline 
WA_MWLI_DAT_STR-LSTFL sy-vline 
WA_MWLI_DAT_STR-LSTVZ sy-vline 
WA_MWLI_DAT_STR-LSTAK sy-vline 
WA_MWLI_DAT_STR-LDVFL sy-vline 
WA_MWLI_DAT_STR-LDBFL sy-vline 
WA_MWLI_DAT_STR-LDVZL sy-vline 
WA_MWLI_DAT_STR-LDBZL sy-vline 
WA_MWLI_DAT_STR-VDVFL sy-vline 
WA_MWLI_DAT_STR-VDBFL sy-vline 
WA_MWLI_DAT_STR-VDVZL sy-vline 
WA_MWLI_DAT_STR-VDBZL sy-vline      INTO ld_text SEPARATED BY SPACE.

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