Explain EXPLAIN QUERY TREE (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Identifier t1.value
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Subquery (alias t1) (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 3)
           ExpressionList (children 1)
            Function if (alias value) (children 1)
             ExpressionList (children 3)
              Function greater (children 1)
               ExpressionList (children 2)
                Identifier number
                Literal UInt64_5
              Literal \'censor.net\'
              Literal \'google\'
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              TableIdentifier system.numbers
           Literal UInt64_10
