Explain EXPLAIN QUERY TREE (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 1)
     Function if (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
