public function topChildrenExpr() { $cols = RelatedStat::columns(); $expr = RelatedStat::statement()->select('? AS symbol_id', $cols->childSymbolId)->where('? IN (?)', $cols->runId, $this->runIds)->where('? = ?', $cols->parentSymbolId, $this->symbolId)->groupBy($cols->childSymbolId); return $expr; }