跨库join、orderbylimit 等现在支持了么？

我看邱硕的 ppt 里：
分页排序：

```
SELECT c1 FROM tb1 ORDER BY c1 LIMIT 4, 2
```

跨库join：

```
SELECT *
FROM tb1 INNER JOIN tb2
ON t1.MEMBER_ID=t2.NAME
WHERE t1.gmt>600
AND t2.time>600
```

都是ok的？

Start by running the posted ORDER BY/LIMIT and cross-database JOIN queries against Cobar, then inspect the relevant query-routing behavior if either result is unsupported. Done means both forms have a confirmed support status, with any limitations recorded in the issue.

Written by the indexing model from the issue text.