Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 2)
     Function CAST (alias c) (children 1)
      ExpressionList (children 2)
       Identifier number
       Literal \'UInt8\'
     Function toTypeName (children 1)
      ExpressionList (children 1)
       Identifier c
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Function numbers (children 1)
        ExpressionList (children 1)
         Literal UInt64_1