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