Extracting years in MySQL can use the YEAR() function, 1. Use YEAR(date_column) to extract years from DATE, DATETIME or TIMESTAMP type fields; 2. It is often used to count annual data volume, group by year, or filter specific year records; 3. Use WHERE YEAR(date_column) when querying. The data can be filtered, but may affect index performance; 4. It is recommended to replace it with range query to improve efficiency, such as WHERE date_column >= 'YYYY-01-01' AND date_column
Extracting years from dates in MySQL is a very common requirement, such as if you want to count the total amount of data for a certain year, or filter out records for a certain year. There is no need for complicated operations at this time, you can do it with a built-in function.
Extract year using YEAR() function
MySQL provides the YEAR() function that extracts years directly from fields of date or datetime type. It is very simple to use:
SELECT YEAR(order_date) AS order_year FROM orders;
The above example extracts the year from the order_date field of orders table. This function is suitable for fields of type DATE , DATETIME , and TIMESTAMP .
Common scenarios include:
- Statistics of the order quantity per year
- Display data trends by grouping
- Query data for a specific year (such as
WHERE YEAR(create_time) = 2023)
Use year filtering in query conditions
If you want to find data for a certain year, you can use the YEAR() function in WHERE condition:
SELECT * FROM sales WHERE YEAR(sale_date) = 2022;
This allows you to filter out all sales records for 2022. But it should be noted that this writing method may not be able to effectively utilize indexes, especially when the table data is large, it will affect query performance.
If you often need to query by year, it is recommended:
- Add a separate year field and index it
- Or use a scope query instead of
YEAR(), for example:
SELECT * FROM sales WHERE sale_date >= '2022-01-01' AND sale_date < '2023-01-01';
This approach is usually more efficient because the database can use indexes on sale_date .
Combined with GROUP BY Group Statistics by Year
When doing data summary, it is often necessary to group statistics by year. For example, counting annual sales:
SELECT YEAR(order_date) AS order_year, SUM(amount) AS total_amount FROM orders GROUP BY YEAR(order_date);
This will result in the total amount for each year. If you want to further refine to a month or quarter, you can also extract the month or quarter fields to group them together.
Need to note:
- If the data for a certain year is empty, the result will not show that year.
- You can cooperate with
ORDER BYto make the results sorted by year more intuitive
Basically that's it. Using YEAR() is the most direct way, but performance issues must be considered in large amounts of data. The writing method may be better if you use it in another way.
The above is the detailed content of mysql get year from date. For more information, please follow other related articles on the PHP Chinese website!
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