ABAP Select data from SAP table MC45W_2LST into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP MC45W_2LST 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 MC45W_2LST. 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 MC45W_2LST 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_MC45W_2LST TYPE STANDARD TABLE OF MC45W_2LST,
      WA_MC45W_2LST TYPE MC45W_2LST,
      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: <MC45W_2LST> TYPE MC45W_2LST.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_MC45W_2LST.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM MC45W_2LST
  INTO TABLE IT_MC45W_2LST.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM MC45W_2LST
*  INTO TABLE @DATA(IT_MC45W_2LST2).
*--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_MC45W_2LST INDEX 1 INTO DATA(WA_MC45W_2LST2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_MC45W_2LST ASSIGNING <MC45W_2LST>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<MC45W_2LST>-KUNRE = 1.
<MC45W_2LST>-KUNRG = 1.
<MC45W_2LST>-KWERT_RL = 1.
<MC45W_2LST>-LFTYP = 1.
<MC45W_2LST>-LIFRE = 1.

ENDLOOP.

LOOP AT IT_MC45W_2LST INTO WA_MC45W_2LST.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_MC45W_2LST-LNRZB, sy-vline,
  WA_MC45W_2LST-LOGSYS, sy-vline,
  WA_MC45W_2LST-MWSBP, sy-vline,
  WA_MC45W_2LST-MWSBP_RL, sy-vline,
  WA_MC45W_2LST-NAVNW, sy-vline,
  WA_MC45W_2LST-NETWR, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_MC45W_2LST 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_MC45W_2LST 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_MC45W_2LST INTO WA_MC45W_2LST.


*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 ALPHA, internal->external for field KUNRE
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_MC45W_2LST-KUNRE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MC45W_2LST-KUNRE.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field KUNRG
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_MC45W_2LST-KUNRG
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MC45W_2LST-KUNRG.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field LIFRE
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_MC45W_2LST-LIFRE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MC45W_2LST-LIFRE.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field LNRZB
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_MC45W_2LST-LNRZB
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MC45W_2LST-LNRZB.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field LOGSYS
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_MC45W_2LST-LOGSYS
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MC45W_2LST-LOGSYS.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field WBELN
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_MC45W_2LST-WBELN
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MC45W_2LST-WBELN.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field WBELN_LF
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_MC45W_2LST-WBELN_LF
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_MC45W_2LST-WBELN_LF.
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_MC45W_2LST_STR, 
KUNRE TYPE STRING,
KUNRG TYPE STRING,
KWERT_RL TYPE STRING,
LFTYP TYPE STRING,
LIFRE TYPE STRING,
LNRZB TYPE STRING,
LOGSYS TYPE STRING,
MWSBP TYPE STRING,
MWSBP_RL TYPE STRING,
NAVNW TYPE STRING,
NETWR TYPE STRING,
POSNR TYPE STRING,
WBELN TYPE STRING,
WBELN_LF TYPE STRING,END OF T_EKKO_STR.
DATA: WA_MC45W_2LST_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_MC45W_2LST_STR-KUNRE sy-vline 
WA_MC45W_2LST_STR-KUNRG sy-vline 
WA_MC45W_2LST_STR-KWERT_RL sy-vline 
WA_MC45W_2LST_STR-LFTYP sy-vline 
WA_MC45W_2LST_STR-LIFRE sy-vline 
WA_MC45W_2LST_STR-LNRZB sy-vline 
WA_MC45W_2LST_STR-LOGSYS sy-vline 
WA_MC45W_2LST_STR-MWSBP sy-vline 
WA_MC45W_2LST_STR-MWSBP_RL sy-vline 
WA_MC45W_2LST_STR-NAVNW sy-vline 
WA_MC45W_2LST_STR-NETWR sy-vline 
WA_MC45W_2LST_STR-POSNR sy-vline 
WA_MC45W_2LST_STR-WBELN sy-vline 
WA_MC45W_2LST_STR-WBELN_LF sy-vline      INTO ld_text SEPARATED BY SPACE.

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