mysql按照小时
时间: 2023-07-01 16:28:35 浏览: 112
如果您想在MySQL中按小时进行查询,可以使用DATE_FORMAT函数将日期时间戳转换为小时格式,然后使用GROUP BY子句将结果按小时分组。
以下是一个示例查询,该查询将按小时统计订单数量:
```
SELECT DATE_FORMAT(order_date, '%Y-%m-%d %H:00:00') AS hour, COUNT(*) AS order_count
FROM orders
GROUP BY hour;
```
该查询将订单日期(order_date)转换为 '%Y-%m-%d %H:00:00' 格式的小时,并将结果按小时分组。您可以根据您的具体需求修改查询中的表名、列名和格式。
相关问题
MYSQL按照小时;按天;按月分组,无数据补0
可以使用 MySQL 的日期函数和 GROUP BY 子句来按照小时、天和月分组。
按小时分组:
```
SELECT DATE_FORMAT(date_column, '%Y-%m-%d %H:00:00') as hour, COUNT(*) as count
FROM table_name
GROUP BY hour;
```
按天分组:
```
SELECT DATE(date_column) as day, COUNT(*) as count
FROM table_name
GROUP BY day;
```
按月分组:
```
SELECT DATE_FORMAT(date_column, '%Y-%m') as month, COUNT(*) as count
FROM table_name
GROUP BY month;
```
如果需要在无数据的情况下补0,可以使用 MySQL 的 IFNULL 函数和子查询来实现:
按小时分组:
```
SELECT hours.hour, IFNULL(data.count, 0) as count
FROM (
SELECT DATE_FORMAT(date_column, '%Y-%m-%d %H:00:00') as hour
FROM table_name
GROUP BY hour
) as hours
LEFT JOIN (
SELECT DATE_FORMAT(date_column, '%Y-%m-%d %H:00:00') as hour, COUNT(*) as count
FROM table_name
GROUP BY hour
) as data ON hours.hour = data.hour;
```
按天分组:
```
SELECT days.day, IFNULL(data.count, 0) as count
FROM (
SELECT DATE(date_column) as day
FROM table_name
GROUP BY day
) as days
LEFT JOIN (
SELECT DATE(date_column) as day, COUNT(*) as count
FROM table_name
GROUP BY day
) as data ON days.day = data.day;
```
按月分组:
```
SELECT months.month, IFNULL(data.count, 0) as count
FROM (
SELECT DATE_FORMAT(date_column, '%Y-%m') as month
FROM table_name
GROUP BY month
) as months
LEFT JOIN (
SELECT DATE_FORMAT(date_column, '%Y-%m') as month, COUNT(*) as count
FROM table_name
GROUP BY month
) as data ON months.month = data.month;
```
按照小时查询mysql里的数据
要查询 MySQL 中的数据,可以使用 SELECT 语句。
例如,如果你想查询 MySQL 中的所有数据,可以使用以下语句:
```
SELECT * FROM table_name;
```
如果你想查询 MySQL 中按小时存储的数据,可以使用以下语句:
```
SELECT * FROM table_name WHERE HOUR(column_name) = hour_value;
```
其中,`table_name` 是表的名称,`column_name` 是时间戳字段的名称,`hour_value` 是你想查询的小时数。
注意:需要使用 MySQL 内置函数 HOUR 来提取时间戳字段中的小时部分。
希望这对你有帮助!
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