Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 1)
    ExpressionList (children 1)
     Function CAST (alias c) (children 1)
      ExpressionList (children 2)
       Function array (children 1)
        ExpressionList (children 3)
         Literal UInt64_1
         Function plus (children 1)
          ExpressionList (children 2)
           Literal UInt64_1
           Literal UInt64_1
         Function plus (children 1)
          ExpressionList (children 2)
           Literal UInt64_1
           Literal UInt64_2
       Literal \'Array(UInt32)\'