having count
时间: 2023-08-29 17:07:26 浏览: 55
"having count" is a clause used in SQL queries to filter the results based on the number of occurrences of a value in a group. It is used in conjunction with the "group by" clause to group the results based on a particular column and then filter them based on the count of occurrences of a specific value in that group.
For example, consider a table "orders" with columns "customer_id" and "order_total". We can use the following query to find the total number of orders for each customer who has placed more than 10 orders:
```
SELECT customer_id, COUNT(*) as order_count
FROM orders
GROUP BY customer_id
HAVING order_count > 10;
```
In this query, we first group the orders by customer_id and count the number of orders for each customer using the "count" function. Then we use the "having" clause to filter the results and only include customers who have placed more than 10 orders.
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