Explain EXPLAIN QUERY TREE (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 2)
     Identifier s
     Function or (children 1)
      ExpressionList (children 3)
       Function equals (children 1)
        ExpressionList (children 2)
         Identifier s
         Literal UInt64_21
       Function equals (children 1)
        ExpressionList (children 2)
         Identifier s
         Literal UInt64_22
       Function equals (children 1)
        ExpressionList (children 2)
         Identifier s
         Literal UInt64_23
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier bug
    Set