ABAP Select data from SAP table P18_01 into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP P18_01 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 P18_01. 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 P18_01 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_P18_01 TYPE STANDARD TABLE OF P18_01,
      WA_P18_01 TYPE P18_01,
      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: <P18_01> TYPE P18_01.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_P18_01.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM P18_01
  INTO TABLE IT_P18_01.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM P18_01
*  INTO TABLE @DATA(IT_P18_012).
*--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_P18_01 INDEX 1 INTO DATA(WA_P18_012).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_P18_01 ASSIGNING <P18_01>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<P18_01>-RECTY = 1.
<P18_01>-PERIOD = 1.
<P18_01>-SEQNR = 1.
<P18_01>-ABKRS = 1.
<P18_01>-FPPER = 1.

ENDLOOP.

LOOP AT IT_P18_01 INTO WA_P18_01.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_P18_01-FPBEG, sy-vline,
  WA_P18_01-FPEND, sy-vline,
  WA_P18_01-IABKRS, sy-vline,
  WA_P18_01-IPERM, sy-vline,
  WA_P18_01-INPER, sy-vline,
  WA_P18_01-IPEND, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_P18_01 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_P18_01 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_P18_01 INTO WA_P18_01.


*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_P18_01_STR, 
RECTY TYPE STRING,
PERIOD TYPE STRING,
SEQNR TYPE STRING,
ABKRS TYPE STRING,
FPPER TYPE STRING,
FPBEG TYPE STRING,
FPEND TYPE STRING,
IABKRS TYPE STRING,
IPERM TYPE STRING,
INPER TYPE STRING,
IPEND TYPE STRING,
JUPER TYPE STRING,
SRTZA TYPE STRING,
PAYTY TYPE STRING,
PAYID TYPE STRING,
VOID TYPE STRING,
BONDT TYPE STRING,
RUNDT TYPE STRING,
RUNTM TYPE STRING,
PERMO TYPE STRING,
VOIDD TYPE STRING,
VOIDT TYPE STRING,
VOIDR TYPE STRING,
PAYDT TYPE STRING,
DUMMY TYPE STRING,
INPTY TYPE STRING,
INPID TYPE STRING,
OCRSN TYPE STRING,
INOCR TYPE STRING,
OCCAT TYPE STRING,
INOCC TYPE STRING,
REVERSAL TYPE STRING,
OUTOFSEQ TYPE STRING,
OOSDATE TYPE STRING,
ARC_GROUP TYPE STRING,
CALCD TYPE STRING,
PERSON TYPE STRING,
PERSDATA TYPE STRING,
BRACKET TYPE STRING,
ORIG_SRTZA TYPE STRING,END OF T_EKKO_STR.
DATA: WA_P18_01_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_P18_01_STR-RECTY sy-vline 
WA_P18_01_STR-PERIOD sy-vline 
WA_P18_01_STR-SEQNR sy-vline 
WA_P18_01_STR-ABKRS sy-vline 
WA_P18_01_STR-FPPER sy-vline 
WA_P18_01_STR-FPBEG sy-vline 
WA_P18_01_STR-FPEND sy-vline 
WA_P18_01_STR-IABKRS sy-vline 
WA_P18_01_STR-IPERM sy-vline 
WA_P18_01_STR-INPER sy-vline 
WA_P18_01_STR-IPEND sy-vline 
WA_P18_01_STR-JUPER sy-vline 
WA_P18_01_STR-SRTZA sy-vline 
WA_P18_01_STR-PAYTY sy-vline 
WA_P18_01_STR-PAYID sy-vline 
WA_P18_01_STR-VOID sy-vline 
WA_P18_01_STR-BONDT sy-vline 
WA_P18_01_STR-RUNDT sy-vline 
WA_P18_01_STR-RUNTM sy-vline 
WA_P18_01_STR-PERMO sy-vline 
WA_P18_01_STR-VOIDD sy-vline 
WA_P18_01_STR-VOIDT sy-vline 
WA_P18_01_STR-VOIDR sy-vline 
WA_P18_01_STR-PAYDT sy-vline 
WA_P18_01_STR-DUMMY sy-vline 
WA_P18_01_STR-INPTY sy-vline 
WA_P18_01_STR-INPID sy-vline 
WA_P18_01_STR-OCRSN sy-vline 
WA_P18_01_STR-INOCR sy-vline 
WA_P18_01_STR-OCCAT sy-vline 
WA_P18_01_STR-INOCC sy-vline 
WA_P18_01_STR-REVERSAL sy-vline 
WA_P18_01_STR-OUTOFSEQ sy-vline 
WA_P18_01_STR-OOSDATE sy-vline 
WA_P18_01_STR-ARC_GROUP sy-vline 
WA_P18_01_STR-CALCD sy-vline 
WA_P18_01_STR-PERSON sy-vline 
WA_P18_01_STR-PERSDATA sy-vline 
WA_P18_01_STR-BRACKET sy-vline 
WA_P18_01_STR-ORIG_SRTZA sy-vline      INTO ld_text SEPARATED BY SPACE.

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