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 plus (children 1)
        ExpressionList (children 2)
         Literal UInt64_1
         Literal UInt64_2
       Literal \'UInt32\'
