Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Literal UInt64_1
    Function equals (children 1)
     ExpressionList (children 2)
      Literal UInt64_1
      Literal UInt64_0