mongodb - 查询中的 mongodb c-driver $orderby

Question

我正在尝试使用 sort ($orderby) 关键字对 mongo 集合进行查询。

这是没有 $orderby 的 bson-query 对象：

bson cmd;
bson_init( &cmd );
bson_append_string( &cmd, "ip", ip.c_str() );
bson_append_start_object( &cmd, "timestamp" );
bson_append_long( &cmd, "$gt", 100 );
bson_append_finish_object( &cmd );
bson_finish( &cmd );

mongo_find( conn, collection, cmd, bson_empty( &empty ), 0, 0, MONGO_SLAVE_OK );

它工作得很好，并返回 5000 个结果。

当我添加 $orderby 对象时（就像这里的 c-driver 示例http://api.mongodb.org/c/current/tutorial.html#complex-queries）：

bson cmd;
bson_init( &cmd );
bson_append_string( &cmd, "ip", ip.c_str() );
bson_append_start_object( &cmd, "timestamp" );
bson_append_long( &cmd, "$gt", 100 );
bson_append_finish_object( &cmd );

bson_append_start_object( &cmd, "$orderby" );
bson_append_int( &cmd, "timestamp", 1 );
bson_append_finish_object( &cmd );

bson_finish( &cmd );
...

我有0个结果。

我做错了什么？

Answer 1

尝试：

bson cmd;
bson_init( &cmd );

bson_append_start_object( &cmd, "$query" );
    bson_append_string( &cmd, "ip", ip.c_str() );
    bson_append_start_object( &cmd, "timestamp" );
        bson_append_long( &cmd, "$gt", 100 );
    bson_append_finish_object( &cmd );
bson_append_finish_object( &cmd );

bson_append_start_object( &cmd, "$orderby" );
    bson_append_int( &cmd, "timestamp", 1 );
bson_append_finish_object( &cmd );

bson_finish( &cmd );