SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    Literal \'keeper:\'
    Function regexpExtract (children 1)
     ExpressionList (children 3)
      Identifier value
      Literal \'(`k`.+?)(\\n|\\\\))\'
      Literal UInt64_1
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.zookeeper
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier path
     Function concat (children 1)
      ExpressionList (children 3)
       Literal \'/clickhouse/databases/\'
       Function currentDatabase (children 1)
        ExpressionList
       Literal \'/metadata\'
