match get vertices error

[Shylock-Hg]

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Describe the bug (required)

(root@nebula) [basketballplayer]> MATCH ()-[e:follow]-() RETURN e LIMIT 10
+----------------------------------------------------+
| e                                                  |
+----------------------------------------------------+
| [:follow "player101"->"player102" @0 {degree: 90}] |
| [:follow "player103"->"player102" @0 {degree: 70}] |
| [:follow "player135"->"player102" @0 {degree: 80}] |
| [:follow "player113"->"player106" @0 {degree: 99}] |
| [:follow "player114"->"player115" @0 {degree: 90}] |
| [:follow "player138"->"player115" @0 {degree: 90}] |
+----------------------------------------------------+
Got 6 rows (time spent 2789/3468 us)

There are more than 10 edges, but don't return so many rows.

Your Environments (required)

• OS: uname -a
• Compiler: g++ --version or clang++ --version
• CPU: lscpu
• Commit id (e.g. e6ddeb2)

How To Reproduce(required)

Steps to reproduce the behavior:

1. Step 1
2. Step 2
3. Step 3

Expected behavior

Additional context

[Shylock-Hg]

Separate from #3494

[Shylock-Hg]

It's caused by we get inbound/outbound edges together. So we will get result from storage like:

follow._src|follow._type|follow._rank|follow._dst|follow.degree|follow._src|follow._type|follow._rank|follow._dst|follow.degree|
__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|"player102"|8|0|"player100"|75|
__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|"player102"|8|0|"player101"|75|
"player102"|-8|0|"player101"|90|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|
"player102"|-8|0|"player103"|70|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|
"player102"|-8|0|"player135"|80|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|
"player106"|-8|0|"player113"|99|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|
"player115"|-8|0|"player114"|90|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|
"player115"|-8|0|"player138"|90|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|
__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|"player129"|8|0|"player116"|90|
__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|__EMPTY__|"player129"|8|0|"player121"|90|

So get edges will result some unexpected error for the duplicate column name.