ABAP日期處理函數

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*& Report  ZQWE
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REPORT  ZQWE.

DATA: DATE1 LIKE SY-DATUM,
      DATE2 LIKE SY-DATUM,
      DATE3 LIKE SY-DATUM,
      DATE4 LIKE SY-DATUM,
      DATE5 LIKE SY-DATUM,
      DATE6 LIKE SY-DATUM,
      DATE7 LIKE SY-DATUM.

DATA: WEEK1 LIKE SCAL-WEEK,
      WEEK2 LIKE SCAL-WEEK.

DATA: DAYS TYPE I.

DATA: SUND TYPE  P.

  DATA: DATE_L LIKE SY-DATUM,
        TIME_L LIKE SY-UZEIT.

PARAMETERS: GJAHR TYPE GJAHR OBLIGATORY,
                       MONAT TYPE MONAT OBLIGATORY,
                       TIME LIKE SY-UZEIT.

"搜尋協助
AT SELECTION-SCREEN ON VALUE-REQUEST FOR GJAHR.
  CALL FUNCTION 'F4_DATE'
   EXPORTING
     DATE_FOR_FIRST_MONTH               = SY-DATUM
   IMPORTING
     SELECT_DATE                        =  DATE_L
   EXCEPTIONS
     CALENDAR_BUFFER_NOT_LOADABLE       = 1
     DATE_AFTER_RANGE                   = 2
     DATE_BEFORE_RANGE                  = 3
     DATE_INVALID                       = 4
     FACTORY_CALENDAR_NOT_FOUND         = 5
     HOLIDAY_CALENDAR_NOT_FOUND         = 6
     PARAMETER_CONFLICT                 = 7
     OTHERS                             = 8
            .
  IF SY-SUBRC = 0.
    GJAHR = DATE_L+0(4).
  ENDIF.

START-OF-SELECTION.

  "某個月第一天
  CONCATENATE GJAHR MONAT '01' INTO DATE1.

  "某個月最後一天
  CALL FUNCTION 'RP_LAST_DAY_OF_MONTHS'
    EXPORTING
      DAY_IN            = DATE1
    IMPORTING
      LAST_DAY_OF_MONTH = DATE2
    EXCEPTIONS
      DAY_IN_NO_DATE    = 1
      OTHERS            = 2.

  "兩個日期之間的天數
  DAYS = DATE2 - DATE1.

  "年度，月份，天數，往前往後推
  CALL FUNCTION 'RP_CALC_DATE_IN_INTERVAL' "從當前的日期往前推3個月得到一個日期
  EXPORTING
    DATE            = DATE2
    DAYS            = 0
    MONTHS          = 1
    SIGNUM          = '+'
    YEARS           = 0
  IMPORTING
    CALC_DATE       = DATE3.

  "根據日期擷取到周數
  CALL FUNCTION 'DATE_GET_WEEK'
    EXPORTING
      DATE         = DATE3
    IMPORTING
      WEEK         = WEEK1
    EXCEPTIONS
      DATE_INVALID = 1
      OTHERS       = 2.

  "擷取該周第一天
  CALL FUNCTION 'WEEK_GET_FIRST_DAY'
    EXPORTING
      WEEK         = WEEK1
    IMPORTING
      DATE         = DATE4
    EXCEPTIONS
      WEEK_INVALID = 1
      OTHERS       = 2.

  "根據周數，擷取下一周周數，星期一與星期天
  CALL FUNCTION 'NEXT_WEEK'
    EXPORTING
      CURRENT_WEEK       =  WEEK1
   IMPORTING
     NEXT_WEEK          = WEEK2
     MONDAY             =  DATE5
     SUNDAY             =     DATE6      .

"根據日期擷取星期幾
"返回為數字，數字與星期X或者monday之類對應關係TABLES: T246.
CALL FUNCTION 'DAY_IN_WEEK'
  EXPORTING
    DATUM         = DATE4
 IMPORTING
   WOTNR         =      SUND     .

WRITE:/ DATE1, DATE2, DAYS, DATE3, WEEK1, DATE4, SUND, WEEK2, DATE5, DATE6.

將日期由內部格式轉換成外部格式，比如'20121020'轉換成'2012.10.20'，BDC的時候可能用到

CONVERT_DATE_TO_EXTERNAL

將日期由外部格式轉成內部格式，從螢幕取值的時候可能用到

CONVERT_DATE_TO_INTERNAL