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 transform (children 1)
        ExpressionList (children 4)
         Identifier number
         Literal Array_[UInt64_2, UInt64_4, UInt64_6]
         Literal Array_[\'google\', \'censor.net\', \'yahoo\']
         Literal \'other\'
       Literal \'1\'
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier system.numbers
    Literal UInt64_10
