Explain EXPLAIN PIPELINE (children 3)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Subquery (alias c0) (children 1)
      SelectWithUnionQuery (children 1)
       ExpressionList (children 1)
        SelectQuery (children 1)
         ExpressionList (children 1)
          Literal UInt64_1
    TablesInSelectQuery (children 2)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Subquery (alias tx) (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 1)
           ExpressionList (children 2)
            Literal UInt64_1 (alias c0)
            Literal UInt64_1 (alias c1)
     TablesInSelectQueryElement (children 2)
      TableExpression (children 1)
       Subquery (alias ty) (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 1)
           ExpressionList (children 2)
            Literal UInt64_0 (alias c0)
            Literal UInt64_1 (alias c1)
      TableJoin (children 1)
       ExpressionList (children 2)
        Identifier c0
        Identifier c1
 Identifier Null
 Set
