SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function tuple (children 1)
     ExpressionList (children 2)
      Subquery (alias time_with_microseconds) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 5)
          ExpressionList (children 1)
           Identifier query_start_time_microseconds
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier system.query_log
          Function equals (children 1)
           ExpressionList (children 2)
            Identifier current_database
            Function currentDatabase (children 1)
             ExpressionList
          ExpressionList (children 1)
           OrderByElement (children 1)
            Identifier query_start_time
          Literal UInt64_1
      Subquery (alias t) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 5)
          ExpressionList (children 2)
           Literal Float64_inf
           Identifier query_start_time
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier system.query_log
          Function equals (children 1)
           ExpressionList (children 2)
            Identifier current_database
            Function currentDatabase (children 1)
             ExpressionList
          ExpressionList (children 1)
           OrderByElement (children 1)
            Identifier query_start_time
          Literal UInt64_1
   ExpressionList (children 1)
    Function if (children 1)
     ExpressionList (children 3)
      Function equals (children 1)
       ExpressionList (children 2)
        Function dateDiff (children 1)
         ExpressionList (children 3)
          Literal \'second\'
          Function toDateTime (children 1)
           ExpressionList (children 1)
            Identifier time_with_microseconds
          Function toDateTime (children 1)
           ExpressionList (children 1)
            Identifier t
        Literal Int64_-9223372036854775808
      Literal \'ok\'
      Literal \'\'
   Set