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)
       Function s3 (alias s) (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
