SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   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 \'\'
