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 tupleElement (children 1)
        ExpressionList (children 2)
         Function CAST (children 1)
          ExpressionList (children 2)
           Function tuple (children 1)
            ExpressionList (children 3)
             Literal UInt64_3
             Literal UInt64_4
             Literal UInt64_5
           Literal \'Tuple(UInt64, UInt64, UInt64)\'
         Literal UInt64_1
       Literal \'Int32\'
