code: func EqualDatums(sc *stmtctx.StatementContext, a []Datum, b []Datum) (bool, error) {
  	if len(a) != len(b) {
  		return false, nil
  	}
  	if a == nil && b == nil {
  		return true, nil
  	}
  	if a == nil || b == nil {
  		return false, nil
  	}
  	for i, ai := range a {
  		v, err := ai.CompareDatum(sc, &b[i])
  		if err != nil {
  			return false, errors.Trace(err)
  		}
  		if v != 0 {
  			return false, nil
  		}
  	}
  	return true, nil
  }
docs: // EqualDatums compare if a and b contains the same datum values.