Explain EXPLAIN QUERY TREE (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 7)
    ExpressionList (children 1)
     Identifier id
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test
    Function in (children 1)
     ExpressionList (children 2)
      Identifier id
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 4)
          ExpressionList (children 1)
           Identifier id
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier test
          ExpressionList (children 1)
           OrderByElement (children 1)
            Identifier id
          Literal UInt64_4
    ExpressionList (children 1)
     OrderByElement (children 1)
      Identifier id
    Literal UInt64_1
    ExpressionList (children 1)
     Identifier id
    Set
