code: func (coll *HistColl) GetRowCountByColumnRanges(sc *stmtctx.StatementContext, colID int64, colRanges []*ranger.Range) (float64, error) {
  	c, ok := coll.Columns[colID]
  	if !ok || c.IsInvalid(sc, coll.Pseudo) {
  		return GetPseudoRowCountByColumnRanges(sc, float64(coll.Count), colRanges, 0)
  	}
  	result, err := c.GetColumnRowCount(sc, colRanges, coll.ModifyCount)
  	result *= c.GetIncreaseFactor(coll.Count)
  	return result, errors.Trace(err)
  }
docs: // GetRowCountByColumnRanges estimates the row count by a slice of Range.