Executing direct MS SQL statements in ax 2012 connecting to external data base.

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How to get AX applciation preiod start date and end date in D365 FO or ax7

PeriodStart             periodStartDate;
PeriodEnd               periodEndDate;

periodStartDate = FiscalCalendarYear::findYearByCalendarDate(Ledger::fiscalCalendar(), DateTimeUtil::getSystemDate(DateTimeUtil::getUserPreferredTimeZone())).StartDate;
        periodEndDate   = FiscalCalendarYear::findYearByCalendarDate(Ledger::fiscalCalendar(), DateTimeUtil::getSystemDate(DateTimeUtil::getUserPreferredTimeZone())).EndDate;