Explain EXPLAIN (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Identifier number
    TablesInSelectQuery (children 2)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier system.numbers (alias n)
     TablesInSelectQueryElement (children 2)
      TableExpression (children 1)
       Subquery (alias s) (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 2)
           ExpressionList (children 1)
            Asterisk
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              Function s3 (children 1)
               ExpressionList (children 2)
                Literal \'http://localhost:11111/test/a.tsv\'
                Literal \'TSV\'
      TableJoin (children 1)
       Function equals (children 1)
        ExpressionList (children 2)
         Function toInt64 (children 1)
          ExpressionList (children 1)
           Identifier n.number
         Function toInt64 (children 1)
          ExpressionList (children 1)
           Identifier s.c1
