ABAP Select data from SAP table P20_AAMST into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP P20_AAMST 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 P20_AAMST. 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 P20_AAMST 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_P20_AAMST TYPE STANDARD TABLE OF P20_AAMST,
      WA_P20_AAMST TYPE P20_AAMST,
      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: <P20_AAMST> TYPE P20_AAMST.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_P20_AAMST.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM P20_AAMST
  INTO TABLE IT_P20_AAMST.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM P20_AAMST
*  INTO TABLE @DATA(IT_P20_AAMST2).
*--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_P20_AAMST INDEX 1 INTO DATA(WA_P20_AAMST2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_P20_AAMST ASSIGNING <P20_AAMST>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<P20_AAMST>-RDATE = 1.
<P20_AAMST>-RTIME = 1.
<P20_AAMST>-MTYPE = 1.
<P20_AAMST>-LONNS = 1.
<P20_AAMST>-ORGNJ = 1.

ENDLOOP.

LOOP AT IT_P20_AAMST INTO WA_P20_AAMST.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_P20_AAMST-ORGNB, sy-vline,
  WA_P20_AAMST-FDNUM, sy-vline,
  WA_P20_AAMST-HIRDA, sy-vline,
  WA_P20_AAMST-CHIRD, sy-vline,
  WA_P20_AAMST-WOHRS, sy-vline,
  WA_P20_AAMST-CWOSI, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_P20_AAMST 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_P20_AAMST 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_P20_AAMST INTO WA_P20_AAMST.


*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_P20_AAMST_STR, 
RDATE TYPE STRING,
RTIME TYPE STRING,
MTYPE TYPE STRING,
LONNS TYPE STRING,
ORGNJ TYPE STRING,
ORGNB TYPE STRING,
FDNUM TYPE STRING,
HIRDA TYPE STRING,
CHIRD TYPE STRING,
WOHRS TYPE STRING,
CWOSI TYPE STRING,
NORGN TYPE STRING,
CORGN TYPE STRING,
FIRDA TYPE STRING,
OCCUP TYPE STRING,
COCCU TYPE STRING,END OF T_EKKO_STR.
DATA: WA_P20_AAMST_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_P20_AAMST_STR-RDATE sy-vline 
WA_P20_AAMST_STR-RTIME sy-vline 
WA_P20_AAMST_STR-MTYPE sy-vline 
WA_P20_AAMST_STR-LONNS sy-vline 
WA_P20_AAMST_STR-ORGNJ sy-vline 
WA_P20_AAMST_STR-ORGNB sy-vline 
WA_P20_AAMST_STR-FDNUM sy-vline 
WA_P20_AAMST_STR-HIRDA sy-vline 
WA_P20_AAMST_STR-CHIRD sy-vline 
WA_P20_AAMST_STR-WOHRS sy-vline 
WA_P20_AAMST_STR-CWOSI sy-vline 
WA_P20_AAMST_STR-NORGN sy-vline 
WA_P20_AAMST_STR-CORGN sy-vline 
WA_P20_AAMST_STR-FIRDA sy-vline 
WA_P20_AAMST_STR-OCCUP sy-vline 
WA_P20_AAMST_STR-COCCU sy-vline      INTO ld_text SEPARATED BY SPACE.

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