Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 1)
    ExpressionList (children 1)
     Function CAST (children 1)
      ExpressionList (children 2)
       Function arrayElement (children 1)
        ExpressionList (children 2)
         Literal Array_[UInt64_3, UInt64_4, UInt64_5]
         Literal UInt64_1
       Literal \'Int32\'
