code: func (ran *Range) IsPoint(sc *stmtctx.StatementContext) bool {
  	if len(ran.LowVal) != len(ran.HighVal) {
  		return false
  	}
  	for i := range ran.LowVal {
  		a := ran.LowVal[i]
  		b := ran.HighVal[i]
  		if a.Kind() == types.KindMinNotNull || b.Kind() == types.KindMaxValue {
  			return false
  		}
  		cmp, err := a.CompareDatum(sc, &b)
  		if err != nil {
  			return false
  		}
  		if cmp != 0 {
  			return false
  		}
  
  		if a.IsNull() {
  			return false
  		}
  	}
  	return !ran.LowExclude && !ran.HighExclude
  }
docs: // IsPoint returns if the range is a point.