| 基本结构 | SELECT expr [[AS] alias] FROM table [WHERE] [GROUP BY] [HAVING] [ORDER BY] [LIMIT] |
|---|---|
| 常用聚合 | count()、sum、avg、min、max、uniq、quantile |
| 特色能力 | LIMIT BY 分组取前 N、WITH TOTALS、WINDOW 子句 |
示例
示例
SELECT
toDate(ts) AS d,
count() AS requests,
round(avg(value), 2) AS avg_value
FROM metrics
WHERE ts >= now() - INTERVAL 7 DAY
GROUP BY d
ORDER BY d;ClickHouse 不允许 SELECT 里用未参与 GROUP BY 的裸列（除 any/argMax 等聚合包裹外），分组口径要写清楚。