public TimestampdiffFunc(IntervalPrimary.UnitType unit, List <Expression> arguments)
     : base("TIMESTAMPADD", arguments)
 {
     this.Unit = unit;
 }
 public ExtractFunc(IntervalPrimary.UnitType unit, IExpression date)
     : base("EXTRACT", WrapList(date))
 {
     this.Unit = unit;
 }