ABAP Select data from SAP table CATR into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM CATR
*  INTO TABLE @DATA(IT_CATR2).
*--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_CATR INDEX 1 INTO DATA(WA_CATR2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<CATR>-ABLNR = 1.
<CATR>-LFDNR = 1.
<CATR>-INDAT = 1.
<CATR>-STAT = 1.
<CATR>-TABNA = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_CATR-VARF1, sy-vline,
  WA_CATR-VARF2, sy-vline,
  WA_CATR-VARF3, sy-vline,
  WA_CATR-VARF4, sy-vline,
  WA_CATR-VARF5, sy-vline,
  WA_CATR-VARF6, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_CATR 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_CATR 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_CATR INTO WA_CATR.


*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_CATR_STR, 
ABLNR TYPE STRING,
LFDNR TYPE STRING,
INDAT TYPE STRING,
STAT TYPE STRING,
TABNA TYPE STRING,
VARF1 TYPE STRING,
VARF2 TYPE STRING,
VARF3 TYPE STRING,
VARF4 TYPE STRING,
VARF5 TYPE STRING,
VARF6 TYPE STRING,
VARF7 TYPE STRING,
VARX8 TYPE STRING,
DEST TYPE STRING,END OF T_EKKO_STR.
DATA: WA_CATR_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_CATR_STR-ABLNR sy-vline 
WA_CATR_STR-LFDNR sy-vline 
WA_CATR_STR-INDAT sy-vline 
WA_CATR_STR-STAT sy-vline 
WA_CATR_STR-TABNA sy-vline 
WA_CATR_STR-VARF1 sy-vline 
WA_CATR_STR-VARF2 sy-vline 
WA_CATR_STR-VARF3 sy-vline 
WA_CATR_STR-VARF4 sy-vline 
WA_CATR_STR-VARF5 sy-vline 
WA_CATR_STR-VARF6 sy-vline 
WA_CATR_STR-VARF7 sy-vline 
WA_CATR_STR-VARX8 sy-vline 
WA_CATR_STR-DEST sy-vline      INTO ld_text SEPARATED BY SPACE.

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