At selection screen event

Question

suppose i have declared parameter on selection screen for carrid and  i want to validate it like this.
suppose when i am putting valid carrid then i am getting the list but if i put another value for carrid and if no values exist in database for carrid then it should show msg that values are not found in table.
please let me know how to do it.

Answer 1

*& Report  ZTEST1
REPORT  ZTEST1.
type-pools: slis.
data:i_sbook type STANDARD TABLE OF sbook initial SIZE 0,
     i_fieldcatalog type SLIS_T_FIELDCAT_ALV,
     wa_sbook type sbook.
select-OPTIONS:
s_CARRID for wa_sbook-carrid.
at SELECTION-SCREEN.
if s_CARRID is not initial.
select count( * )
  from SCARR where CARRID in s_CARRID.
if sy-subrc <> 0.
   MESSAGE e000(ztest) with 'Invalid Airline Code'.
endif.
endif.
START-OF-SELECTION.
select *
  from sbook
  into table i_sbook
  up to 50 rows
  where carrid in s_carrid.
check sy-subrc = 0.
data: l_repid type syrepid value sy-repid.
CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
  EXPORTING
    I_PROGRAM_NAME               = l_repid
    I_INTERNAL_TABNAME           = 'I_SBOOK'
   I_STRUCTURE_NAME             = 'SBOOK'
    I_CLIENT_NEVER_DISPLAY       = 'X'
*   I_INCLNAME                   =
*   I_BYPASSING_BUFFER           =
*   I_BUFFER_ACTIVE              =
  CHANGING
    ct_fieldcat                  = i_fieldcatalog
  EXCEPTIONS
    INCONSISTENT_INTERFACE       = 1
    PROGRAM_ERROR                = 2
    OTHERS                       = 3
IF sy-subrc <> 0.
MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.
data:
      wa_layout type SLIS_LAYOUT_ALV.
wa_layout-confirmation_prompt = 'X'.
CALL FUNCTION 'REUSE_ALV_LIST_DISPLAY'
  EXPORTING
*   I_INTERFACE_CHECK                 = ' '
*   I_BYPASSING_BUFFER                = ' '
*   I_BUFFER_ACTIVE                   = ' '
*   I_CALLBACK_PROGRAM                = ' '
*   I_CALLBACK_PF_STATUS_SET          = ' '
*   I_CALLBACK_USER_COMMAND           = ' '
*   I_CALLBACK_TOP_OF_PAGE            = ' '
*   I_CALLBACK_HTML_TOP_OF_PAGE       = ' '
*   I_CALLBACK_HTML_END_OF_LIST       = ' '
    I_STRUCTURE_NAME                  = 'SBOOK'
*   I_BACKGROUND_ID                   = ' '
*   I_GRID_TITLE                      =
*   I_GRID_SETTINGS                   =
    IS_LAYOUT                         = wa_layout
*    IT_FIELDCAT                       = i_fieldcatalog
*   IT_EXCLUDING                      =
*   IT_SPECIAL_GROUPS                 =
*   IT_SORT                           =
*   IT_FILTER                         =
*   IS_SEL_HIDE                       =
*   I_DEFAULT                         = 'X'
*   I_SAVE                            = ' '
*   IS_VARIANT                        =
*   IT_EVENTS                         =
*   IT_EVENT_EXIT                     =
*   IS_PRINT                          =
*   IS_REPREP_ID                      =
*   I_SCREEN_START_COLUMN             = 0
*   I_SCREEN_START_LINE               = 0
*   I_SCREEN_END_COLUMN               = 0
*   I_SCREEN_END_LINE                 = 0
*   I_HTML_HEIGHT_TOP                 = 0
*   I_HTML_HEIGHT_END                 = 0
*   IT_ALV_GRAPHICS                   =
*   IT_HYPERLINK                      =
*   IT_ADD_FIELDCAT                   =
*   IT_EXCEPT_QINFO                   =
*   IR_SALV_FULLSCREEN_ADAPTER        =
* IMPORTING
*   E_EXIT_CAUSED_BY_CALLER           =
*   ES_EXIT_CAUSED_BY_USER            =
  TABLES
    t_outtab                          = i_sbook
  EXCEPTIONS
    PROGRAM_ERROR                     = 1
    OTHERS                            = 2
IF sy-subrc <> 0.
MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.