--query "INSERT INTO stackoverflow.posts_v2 FORMAT Native"
```
## 예시 쿼리
시작하는 데 도움이 될 몇 가지 간단한 질문입니다.
### Stack Overflow에서 가장 많이 사용된 태그
```sql theme={null}
SELECT
arrayJoin(arrayFilter(t -> (t != ''), splitByChar('|', Tags))) AS Tags,
count() AS c
FROM stackoverflow.posts
GROUP BY Tags
ORDER BY c DESC
LIMIT 10
```
```response theme={null}
┌─Tags───────┬───────c─┐
│ javascript │ 2527130 │
│ python │ 2189638 │
│ java │ 1916156 │
│ c# │ 1614236 │
│ php │ 1463901 │
│ android │ 1416442 │
│ html │ 1186567 │
│ jquery │ 1034621 │
│ c++ │ 806202 │
│ css │ 803755 │
└────────────┴─────────┘
10 rows in set. Elapsed: 1.013 sec. Processed 59.82 million rows, 1.21 GB (59.07 million rows/s., 1.19 GB/s.)
Peak memory usage: 224.03 MiB.
```
### 답변을 가장 많이 한 사용자(활성 계정)
계정에는 `UserId`가 필요합니다.
```sql theme={null}
SELECT
any(OwnerUserId) UserId,
OwnerDisplayName,
count() AS c
FROM stackoverflow.posts WHERE OwnerDisplayName != '' AND PostTypeId='Answer' AND OwnerUserId != 0
GROUP BY OwnerDisplayName
ORDER BY c DESC
LIMIT 5
```
```response theme={null}
┌─UserId─┬─OwnerDisplayName─┬────c─┐
│ 22656 │ Jon Skeet │ 2727 │
│ 23354 │ Marc Gravell │ 2150 │
│ 12950 │ tvanfosson │ 1530 │
│ 3043 │ Joel Coehoorn │ 1438 │
│ 10661 │ S.Lott │ 1087 │
└────────┴──────────────────┴──────┘
5 rows in set. Elapsed: 0.154 sec. Processed 35.83 million rows, 193.39 MB (232.33 million rows/s., 1.25 GB/s.)
Peak memory usage: 206.45 MiB.
```
### 조회 수가 가장 많은 ClickHouse 관련 게시물
```sql theme={null}
SELECT
Id,
Title,
ViewCount,
AnswerCount
FROM stackoverflow.posts
WHERE Title ILIKE '%ClickHouse%'
ORDER BY ViewCount DESC
LIMIT 10
```
```response theme={null}
┌───────Id─┬─Title────────────────────────────────────────────────────────────────────────────┬─ViewCount─┬─AnswerCount─┐
│ 52355143 │ Is it possible to delete old records from clickhouse table? │ 41462 │ 3 │
│ 37954203 │ Clickhouse Data Import │ 38735 │ 3 │
│ 37901642 │ Updating data in Clickhouse │ 36236 │ 6 │
│ 58422110 │ Pandas: How to insert dataframe into Clickhouse │ 29731 │ 4 │
│ 63621318 │ DBeaver - Clickhouse - SQL Error [159] .. Read timed out │ 27350 │ 1 │
│ 47591813 │ How to filter clickhouse table by array column contents? │ 27078 │ 2 │
│ 58728436 │ How to search the string in query with case insensitive on Clickhouse database? │ 26567 │ 3 │
│ 65316905 │ Clickhouse: DB::Exception: Memory limit (for query) exceeded │ 24899 │ 2 │
│ 49944865 │ How to add a column in clickhouse │ 24424 │ 1 │
│ 59712399 │ How to cast date Strings to DateTime format with extended parsing in ClickHouse? │ 22620 │ 1 │
└──────────┴──────────────────────────────────────────────────────────────────────────────────┴───────────┴─────────────┘
10 rows in set. Elapsed: 0.472 sec. Processed 59.82 million rows, 1.91 GB (126.63 million rows/s., 4.03 GB/s.)
Peak memory usage: 240.01 MiB.
```
### 가장 논란이 된 게시물
```sql theme={null}
SELECT
Id,
Title,
UpVotes,
DownVotes,
abs(UpVotes - DownVotes) AS Controversial_ratio
FROM stackoverflow.posts
INNER JOIN
(
SELECT
PostId,
countIf(VoteTypeId = 2) AS UpVotes,
countIf(VoteTypeId = 3) AS DownVotes
FROM stackoverflow.votes
GROUP BY PostId
HAVING (UpVotes > 10) AND (DownVotes > 10)
) AS votes ON posts.Id = votes.PostId
WHERE Title != ''
ORDER BY Controversial_ratio ASC
LIMIT 3
```
```response theme={null}
┌───────Id─┬─Title─────────────────────────────────────────────┬─UpVotes─┬─DownVotes─┬─Controversial_ratio─┐
│ 583177 │ VB.NET Infinite For Loop │ 12 │ 12 │ 0 │
│ 9756797 │ Read console input as enumerable - one statement? │ 16 │ 16 │ 0 │
│ 13329132 │ What's the point of ARGV in Ruby? │ 22 │ 22 │ 0 │
└──────────┴───────────────────────────────────────────────────┴─────────┴───────────┴─────────────────────┘
3 rows in set. Elapsed: 4.779 sec. Processed 298.80 million rows, 3.16 GB (62.52 million rows/s., 661.05 MB/s.)
Peak memory usage: 6.05 GiB.
```
## 출처 표기
`cc-by-sa 4.0` 라이선스에 따라 이 데이터를 제공한 Stack Overflow에 감사드리며, [https://archive.org/details/stackexchange](https://archive.org/details/stackexchange)에 있는 원본 데이터 출처와 Stack Overflow의 노고를 밝힙니다.