Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 5)
   SelectQuery (children 1)
    ExpressionList (children 1)
     Literal UInt64_1
   SelectQuery (children 1)
    ExpressionList (children 1)
     Literal UInt64_1
   SelectQuery (children 1)
    ExpressionList (children 1)
     Literal UInt64_1
   SelectQuery (children 1)
    ExpressionList (children 1)
     Literal UInt64_1
   SelectQuery (children 1)
    ExpressionList (children 1)
     Literal UInt64_1