Explain EXPLAIN (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 1)
     Identifier id
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test_table
    Function in (children 1)
     ExpressionList (children 2)
      Function tuple (children 1)
       ExpressionList (children 2)
        Identifier id
        Identifier value
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 2)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Literal UInt64_42
           Literal \'not a number\'
         SelectQuery (children 2)
          ExpressionList (children 2)
           Literal UInt64_5
           Function toString (children 1)
            ExpressionList (children 1)
             Identifier number
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             Function numbers (children 1)
              ExpressionList (children 1)
               Literal UInt64_5
