Date/Time Formula
日付型に変換する
IF( OR(
Event_Start_Date__c< DATETIMEVALUE(DATE(YEAR(DATEVALUE(Event_Start_Date__c)),3,14)
-(WEEKDAY(DATE(YEAR(DATEVALUE(Event_Start_Date__c)),3,14))-1))+15/24,
Event_Start_Date__c> DATETIMEVALUE(DATE(YEAR(DATEVALUE(Event_Start_Date__c)),11,7)
-(WEEKDAY(DATE(YEAR(DATEVALUE(Event_Start_Date__c)),11,7))-1))+15/24
),
TEXT(
HOUR(TIMEVALUE(Event_Start_Date__c-7/24))
-IF(HOUR(TIMEVALUE(Event_Start_Date__c-7/24))>23,24,0)-
IF(HOUR(TIMEVALUE(Event_Start_Date__c-7/24))
-IF(HOUR(TIMEVALUE(Event_Start_Date__c-7/24))>23,24,0)>12, 12,0))+":"+
LPAD(TEXT(MINUTE( TIMEVALUE(Event_Start_Date__c  ))),2, "0")+
IF(HOUR(TIMEVALUE(Event_Start_Date__c-7/24))
-IF(HOUR(TIMEVALUE(Event_Start_Date__c-7/24))>23,24,0)>11, " P"," A")
,
TEXT(
HOUR(TIMEVALUE(Event_Start_Date__c-6/24))
-IF(HOUR(TIMEVALUE(Event_Start_Date__c-6/24))>23,24,0)-
IF(HOUR(TIMEVALUE(Event_Start_Date__c-6/24))
-IF(HOUR(TIMEVALUE(Event_Start_Date__c-6/24))>23,24,0)>12,12,0))

+":"+
LPAD(TEXT(MINUTE( TIMEVALUE(Event_Start_Date__c ))),2, "0")+
IF(HOUR(TIMEVALUE(Event_Start_Date__c-6/24))
-IF(HOUR(TIMEVALUE(Event_Start_Date__c-6/24))>23,24,0)>11, " P"," A")

)
+"M"