create or alter procedure LASTDAY (
    DDATE Date)
returns (
    ODATE Date)
as
begin
    ODATE = DateAdd( 1 month to DDATE ) - extract( Day from DDATE );
    suspend;
end

create or alter procedure LASTDAY (
    DDATE date)
returns (
    ODATE date)
AS
begin
    --ODATE = DateAdd( -1 day to DateAdd( 1 month to DateAdd( -Extract( Day from DDATE ) + 1 day to DDATE ) ) );
    ODATE = DateAdd( 1 month to DDATE - (Extract( Day from DDATE ) - 1) ) - 1;
    suspend;
end

create or alter procedure C$GET_DATE_INFO (
    IN_DATE date)
returns (
    MONTH_BEGIN date,
    MONTH_END date,
    MONTH_LENGTH integer,
    YEAR_BEGIN date,
    YEAR_END date,
    YEAR_LENGTH integer,
    QUARTER smallint,
    QUARTER_BEGIN date,
    QUARTER_END date,
    QUARTER_LENGTH integer)
AS
/*  */
    declare variable LMONTH Integer;
    declare variable LYEAR Integer;
    declare variable LM Integer;
    declare variable LY Integer;
begin
    ------------------------------------------------------------------------------------------------
    -- Процедура вычисляет по заданной во входном параметре дате некоторые другие даты:
    --  - начало и конец месяца, содержащего заданную дату
    --  - начало и конец года, содержащего заданную дату
    --  - номер, начало и конец квартала, содержащего заданную дату
    ------------------------------------------------------------------------------------------------

    if (IN_DATE is not Null) then
      begin
        LMONTH = Extract(Month from IN_DATE);
        LYEAR = Extract(Year from IN_DATE);

        -- месяц
        LM = LMONTH + 1;
        LY = LYEAR;
        MONTH_BEGIN = Cast(LY || '-' || LMONTH || '-01' as Date);
        while (LM > 12) do
          begin
            LM = LM - 12;
            LY = LY + 1;
          end
        MONTH_END = Cast(LY || '-' || LM || '-01' as Date) - 1;

        -- год
        YEAR_BEGIN = Cast(LYEAR || '-01-01' as Date);
        YEAR_END = Cast(LYEAR || '-12-31' as Date);

        -- квартал
        QUARTER = (LMONTH - 1) / 3 + 1;
        LM = (QUARTER - 1) * 3 + 1;
        LY = LYEAR;
        QUARTER_BEGIN = Cast(LY || '-' || LM || '-01' as Date);
        LM = LM + 3;
        while (LM > 12) do
          begin
            LM = LM - 12;
            LY = LY + 1;
          end
        QUARTER_END = Cast(LY || '-' || LM || '-01' as Date) - 1;

        -- продолжительности...
        MONTH_LENGTH = MONTH_END - MONTH_BEGIN + 1;
        YEAR_LENGTH = YEAR_END - YEAR_BEGIN + 1;
        QUARTER_LENGTH = QUARTER_END - QUARTER_BEGIN + 1;
      end

    -- процедура возвращает что-то в любом случае
    suspend;
end