Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 1)
     Function count (children 1)
      ExpressionList
    TablesInSelectQuery (children 2)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Subquery (alias t) (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 3)
           ExpressionList (children 2)
            Function array (alias a) (children 1)
             ExpressionList (children 1)
              Identifier number
            Function array (alias b) (children 1)
             ExpressionList (children 1)
              Function multiply (children 1)
               ExpressionList (children 2)
                Identifier number
                Literal UInt64_2
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              TableIdentifier system.numbers
           Literal UInt64_1
     TablesInSelectQueryElement (children 1)
      ArrayJoin (children 1)
       ExpressionList (children 2)
        Identifier a
        Identifier b
    Function not (children 1)
     ExpressionList (children 1)
      Function ignore (children 1)
       ExpressionList (children 1)
        Function plus (children 1)
         ExpressionList (children 2)
          Identifier a
          Identifier b
