ABAP Select data from SAP table CNMSEG into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM CNMSEG
*  INTO TABLE @DATA(IT_CNMSEG2).
*--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_CNMSEG INDEX 1 INTO DATA(WA_CNMSEG2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<CNMSEG>-MANDT = 1.
<CNMSEG>-MBLNR = 1.
<CNMSEG>-MJAHR = 1.
<CNMSEG>-ZEILE = 1.
<CNMSEG>-RSNUM = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_CNMSEG-RSPOS, sy-vline,
  WA_CNMSEG-BUDAT, sy-vline,
  WA_CNMSEG-KZEAR, sy-vline,
  WA_CNMSEG-MENGE, sy-vline,
  WA_CNMSEG-MEINS, sy-vline,
  WA_CNMSEG-SHKZG, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_CNMSEG 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_CNMSEG 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_CNMSEG INTO WA_CNMSEG.


*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 MBLNR
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_CNMSEG-MBLNR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_CNMSEG-MBLNR.
WRITE:/ 'New Value:', ld_input.

*Conversion exit GJAHR, internal->external for field MJAHR
CALL FUNCTION 'CONVERSION_EXIT_GJAHR_OUTPUT'
  EXPORTING
    input =                      WA_CNMSEG-MJAHR
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_CNMSEG-MJAHR.
WRITE:/ 'New Value:', ld_input.

*Conversion exit CUNIT, internal->external for field MEINS
CALL FUNCTION 'CONVERSION_EXIT_CUNIT_OUTPUT'
  EXPORTING
    input =                      WA_CNMSEG-MEINS
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_CNMSEG-MEINS.
WRITE:/ 'New Value:', ld_input.

*Conversion exit ALPHA, internal->external for field EBELN
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input =                      WA_CNMSEG-EBELN
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_CNMSEG-EBELN.
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_CNMSEG_STR, 
MANDT TYPE STRING,
MBLNR TYPE STRING,
MJAHR TYPE STRING,
ZEILE TYPE STRING,
RSNUM TYPE STRING,
RSPOS TYPE STRING,
BUDAT TYPE STRING,
KZEAR TYPE STRING,
MENGE TYPE STRING,
MEINS TYPE STRING,
SHKZG TYPE STRING,
EBELN TYPE STRING,
EBELP TYPE STRING,
BWART TYPE STRING,END OF T_EKKO_STR.
DATA: WA_CNMSEG_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_CNMSEG_STR-MANDT sy-vline 
WA_CNMSEG_STR-MBLNR sy-vline 
WA_CNMSEG_STR-MJAHR sy-vline 
WA_CNMSEG_STR-ZEILE sy-vline 
WA_CNMSEG_STR-RSNUM sy-vline 
WA_CNMSEG_STR-RSPOS sy-vline 
WA_CNMSEG_STR-BUDAT sy-vline 
WA_CNMSEG_STR-KZEAR sy-vline 
WA_CNMSEG_STR-MENGE sy-vline 
WA_CNMSEG_STR-MEINS sy-vline 
WA_CNMSEG_STR-SHKZG sy-vline 
WA_CNMSEG_STR-EBELN sy-vline 
WA_CNMSEG_STR-EBELP sy-vline 
WA_CNMSEG_STR-BWART sy-vline      INTO ld_text SEPARATED BY SPACE.

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