How to get data within one day in mysql

MySQL is an open source relational database management system that is widely used in Web development. In the daily development process, we often need to obtain information in the database through queries. For some situations where you need to query data within a day, MySQL provides a variety of query methods to achieve this purpose.

Below, we will introduce some commonly used MySQL query statements to obtain data within a day.

1. Query data on a specified date

By using MySQL's date functions, such as the DATE() function and NOW() function, you can query data on a specified date. For example, if we want to query all data on February 20, 2022, we can use the following statement:

SELECT * FROM table_name WHERE DATE(date_column) = '2022-02-20';

Among them, table_name represents the table name, and date_column represents the name of the date field that needs to be queried. This statement will return all data matching the specified date.

2. Query the current day’s data

If you need to query the current day’s data, you can use MySQL’s CURDATE() function. This function will return today's date and then compare it to the field of the desired query. For example, to query all data for today's day, you can use the following statement:

SELECT * FROM table_name WHERE DATE(date_column) = CURDATE();

This will return all data that matches today's date.

3. Querying yesterday’s data

Similarly, if you need to query yesterday’s data, you can use MySQL’s DATE_SUB() function and CURDATE() function. The DATE_SUB() function can be used to reduce a period of time, such as removing one day (INTERVAL 1 DAY). So you can subtract a day from the CURDATE() function to get yesterday's date and then compare it to the field you want to query. For example, to query all data for yesterday, you can use the following statement:

SELECT * FROM table_name WHERE DATE(date_column) = DATE_SUB(CURDATE(), INTERVAL 1 DAY);

This will return all data that matches yesterday's date.

4. Query the data of the last 24 hours

If you need to query the data of the last 24 hours, you can use MySQL's DATE_SUB() function and the INTERVAL keyword. The DATE_SUB() function can be used to subtract a period of time, such as removing a day. The INTERVAL keyword can be used to specify the time interval type, such as HOUR, MINUTE or SECOND. Therefore, you can subtract 24 hours (INTERVAL 24 HOUR) from the DATE_SUB() function to get the date for the last 24 hours, and then compare it with the field you want to query. For example, to query all data in the last 24 hours, you can use the following statement:

SELECT * FROM table_name WHERE date_column BETWEEN DATE_SUB(NOW(), INTERVAL 24 HOUR) AND NOW();

Here, we use the BETWEEN keyword to select all data within the date range from date_column. The NOW() function is used to get the current date and time.

Summary

Through the above four query methods, we can effectively query the data within a day in the MySQL database. It is important to note that if there is no explicit date field in the database design, these queries may require more work and calculations.

In addition to the above query methods, MySQL has many other functions and operations that can be used to manage and operate the database. Mastering these features can not only increase development efficiency, but also improve system performance and security.

Finally, it is recommended to use MySQL's official documentation and reference manuals as much as possible to obtain the latest and most comprehensive information. At the same time, you can also join MySQL-related communities and forums to communicate and share experiences with other developers.

The above is the detailed content of How to get data within one day in mysql. For more information, please follow other related articles on the PHP Chinese website!