What does having mean in mysql

HAVING clause is used to filter the grouped result set and is applied to the summarized data rather than the original data. It can discard rows that do not meet the criteria, refine the result set, and extract specific information. For example, this query finds orders with sales greater than $100: SELECT customer_id, SUM(amount) AS total_amount FROM orders GROUP BY customer_id HAVING total_amount > 100;

In MySQL, the meaning of HAVING

The HAVING clause is used to further filter the result set grouped by GROUP BY. It is similar to the WHERE clause, but applies to aggregated data rather than raw data.

Usage scenarios

The HAVING clause is usually used to filter out rows that meet specific conditions from grouped data. For example:

• Find orders with sales greater than $100.
• Find the orders where each customer purchased more than 5 items.

##Grammar

The syntax of the HAVING clause is as follows:

<code>HAVING <条件></code>

where

is any Valid SQL expressions can include aggregate functions (such as SUM, COUNT, etc.) and comparison operators (such as =, >, <, etc.).

Function

The HAVING clause can provide the following functions by filtering the grouped data:

Discard rows that do not meet the conditions
Further refine the result set
Extract specific information

Example

The following example query finds sales greater than 100 USD orders:

SELECT customer_id, SUM(amount) AS total_amount
FROM orders
GROUP BY customer_id
HAVING total_amount > 100;
This query returns the following results:

##customer_id123 


total_amount
 


120.50


150.75


115.20



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