MySQL使用集合函数进行查询操作实例详解

本文实例讲述了MySQL使用集合函数进行查询操作。分享给大家供大家参考，具体如下：

COUNT函数

SELECT COUNT(*) AS cust_num from customers;SELECT COUNT(c_email) AS email_num FROM customers;SELECT o_num, COUNT(f_id) FROM orderitems GROUP BY o_num;

SELECT SUM(quantity) AS items_total FROM orderitems WHERE o_num = 30005;SELECT o_num, SUM(quantity) AS items_total FROM orderitems GROUP BY o_num;

SELECT AVG(f_price) AS avg_price FROM fruits WHERE s_id = 103;SELECT AVG(f_price) AS avg_price FROM fruits group by s_id;

SELECT MAX(f_price) AS max_price FROM fruits;SELECT s_id, MAX(f_price) AS max_price FROM fruits GROUP BY s_id;SELECT MAX(f_name) from fruits;

SELECT MIN(f_price) AS min_price FROM fruits;SELECT s_id, MIN(f_price) AS min_price FROM fruits GROUP BY s_id;

SELECT COUNT(*) AS cust_num from customers;

SELECT COUNT(c_email) AS email_numFROM customers;

SELECT o_num, COUNT(f_id) FROM orderitems GROUP BY o_num;

SELECT SUM(quantity) AS items_totalFROM orderitemsWHERE o_num = 30005;

SELECT o_num, SUM(quantity) AS items_totalFROM orderitemsGROUP BY o_num;

SELECT AVG(f_price) AS avg_priceFROM fruitsWHERE s_id = 103;

SELECT s_id,AVG(f_price) AS avg_priceFROM fruitsGROUP BY s_id;

mysql>SELECT MAX(f_price) AS max_price FROM fruits;

SELECT s_id, MAX(f_price) AS max_priceFROM fruitsGROUP BY s_id;

SELECT MAX(f_name) from fruits;

mysql>SELECT MIN(f_price) AS min_price FROM fruits;

SELECT s_id, MIN(f_price) AS min_priceFROM fruitsGROUP BY s_id;

希望本文所述对大家MySQL数据库计有所帮助。

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