Explain EXPLAIN AST (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 1)
    ExpressionList (children 1)
     Function equals (children 1)
      ExpressionList (children 2)
       Function isNotDistinctFrom (children 1)
        ExpressionList (children 2)
         Literal UInt64_1
         Literal UInt64_1
       Literal UInt64_1
