【sql语法教学】HAVING子句 | The HAVING Clause 在数据库查询中,SQL语法是一门值得深入研究的技术。作为小编,我很高兴能为大家深入解析HAVING子句的概念及其应用。HAVING子句在SQL中主要用于对聚合函数的结果进行筛选,其允许开发者在执行GROUP BY查询后,对结果进行进一步的条件过滤。这使得它在数据分析中显得尤为重要。
TheHAVINGclause was added to SQL because theWHEREclause cannot be used with aggregate functions. Aggregate functions are often used withGROUP BYclauses, and by addingHAVINGwe can write condition like we do withWHEREclauses. Example List only countries that are represented more than 5 times: ...
Example - Using COUNT function Let's look at how we could use the HAVING clause with the SQL COUNT function. You could use the SQL COUNT function to return the name of the department and the number of employees (in the associated department) that make over $25,000 / year. The SQL ...
You can even use the WHERE clause without HAVING or GROUP BY, as you have seen many times. On the other hand, HAVING can only be used if grouping has been performed using theGROUP BY clause in the SQL query. This is a modal window. ...
Example 1: Let us assume a scenario where we need to find the “film” categories that contains more than 10 films. WE can use the HAVING COUNT clause as shown in the following: SELECT category.name, COUNT(film.film_id)AStotal_films ...
In SQL Server, the HAVING clause includes one or more conditions that should be TRUE for groups of records. It is like the WHERE clause of the GROUP BY clause. The only difference is that the WHERE clause cannot be used with aggregate functions, whereas the HAVING clause can use aggregate...
Example: Correlated subquery in a HAVING clause Suppose that you want a list of all the departments whose average salaries are higher than the average salaries of their areas (all departments whose WORKDEPT begins with the same letter belong to the same area). To get this information, SQL ...
http://.tutorialspoint/sql/sql-having-clause.htmCopyright©tutorialspoint SQL-HAVINGCLAUSE TheHAVINGclauseenablesyoutospecifyconditionsthatfilterwhichgroupresultsappearinthefinalresults. TheWHEREclauseplacesconditionsontheselectedcolumns,whereastheHAVINGclauseplacesconditions ...
SELECTorder_id,SUM(unit_price * quantity) order_valueFROMorder_itemsGROUPBYorder_idHAVINGSUM(unit_price * quantity) >1000000ORDERBYorder_valueDESC;Code language:SQL (Structured Query Language)(sql) Try it Output: In this example: First, theGROUP BYclause groups orders by their ids and calculate...
Note: In the execution order of SQL clauses, `HAVING` is processed after `GROUP BY` and before `ORDER BY`. Examples 1. Basic HAVING Usage SELECT department, COUNT(employee_id) AS num_employees FROM employees GROUP BY department HAVING num_employees > 5; Powered By This example retrieve...