MySQL子查询操作实例详解
编程学习 2021-07-05 14:36www.dzhlxh.cn编程入门
这篇文章主要介绍了MySQL子查询操作,结合实例形式较为详细的分析了mysql表的创建、常见子查询运算与关键字使用技巧,需要的朋友可以参考下
本文实例总结了MySQL子查询操作。分享给大家供大家参考，具体如下：
定义两个表tb1和tb2
CREATE table tbl1 ( num1 INT NOT NULL); CREATE table tbl2 ( num2 INT NOT NULL);
向两个表中插入数据：
INSERT INTO tbl1 values(1), (5), (13), (27); INSERT INTO tbl2 values(6), (14), (11), (20);
any some关键字的子查询
SELECT num1 FROM tbl1 WHERE num1 > ANY (SELECT num2 FROM tbl2);
all关键字的子查询
SELECT num1 FROM tbl1 WHERE num1 > ALL (SELECT num2 FROM tbl2);
exists关键字的子查询
SELECT * from fruits WHERE EXISTS (SELECT s_name FROM suppliers WHERE s_id = 107); SELECT * from fruits WHERE f_price>10.20 AND EXISTS (SELECT s_name FROM suppliers WHERE s_id = 107); SELECT * from fruits WHERE NOT EXISTS (SELECT s_name FROM suppliers WHERE s_id = 107);
带in关键字的子查询
SELECT c_id FROM orders WHERE o_num IN (SELECT o_num FROM orderitems WHERE f_id = 'c0'); SELECT c_id FROM orders WHERE o_num NOT IN (SELECT o_num FROM orderitems WHERE f_id = 'c0');
带比较运算符的子查询
SELECT s_id, f_name FROM fruits WHERE s_id = (SELECT s1.s_id from suppliers AS s1 WHERE s1.s_city = 'Tianjin');
<>所有非
SELECT s_id, f_name FROM fruits WHERE s_id <> (SELECT s1.s_id from suppliers AS s1 WHERE s1.s_city = 'Tianjin');
定义两个表tb1和tb2
CREATE table tbl1 ( num1 INT NOT NULL); CREATE table tbl2 ( num2 INT NOT NULL);
向两个表中插入数据
INSERT INTO tbl1 values(1), (5), (13), (27); INSERT INTO tbl2 values(6), (14), (11), (20);
【例.53】返回tbl2表的所有 num2 列，然后将 tbl1 中的 num1 的值与之进行比较，只要大于 num2的任何值为符合查询条件的结果
SELECT num1 FROM tbl1 WHERE num1 > ANY (SELECT num2 FROM tbl2);
【例.54】返回tbl1表的中比tbl2表num2 列所有值都大的值
SELECT num1 FROM tbl1 WHERE num1 > ALL (SELECT num2 FROM tbl2);
【例.55】查询表suppliers表中是否存在s_id=107的供应商，如果存在则查询fruits表中的记录
SELECT * from fruits WHERE EXISTS (SELECT s_name FROM suppliers WHERE s_id = 107);
【例.56】查询表suppliers表中是否存在s_id=107的供应商，如果存在则查询fruits表中的f_price大于10.20的记录
SELECT * from fruits WHERE f_price>10.20 AND EXISTS (SELECT s_name FROM suppliers WHERE s_id = 107);
【例.57】查询表suppliers表中是否存在s_id=107的供应商，如果不存在则查询fruits表中的记录
SELECT * from fruits WHERE NOT EXISTS (SELECT s_name FROM suppliers WHERE s_id = 107);
【例.58】在orderitems表中查询订购f_id为c0的订单号，并根据订单号查询具有订单号的客户c_id
SELECT c_id FROM orders WHERE o_num IN (SELECT o_num FROM orderitems WHERE f_id = 'c0');
【例.59】与前一个例子语句类似，但是在SELECT语句中使用NOT IN操作符
SELECT c_id FROM orders WHERE o_num NOT IN (SELECT o_num FROM orderitems WHERE f_id = 'c0');
【例.60】在suppliers表中查询s_city等于Tianjin的供应商s_id，然后在fruits表中查询所有该供应商提供的水果的种类
SELECT s_id, f_name FROM fruits WHERE s_id = (SELECT s1.s_id from suppliers AS s1 WHERE s1.s_city = 'Tianjin');
【例.61】在suppliers表中查询s_city等于Tianjin的供应商s_id，然后在fruits表中查询所有非该供应商提供的水果的种类，SQL语句如下：
SELECT s_id, f_name FROM fruits WHERE s_id <> (SELECT s1.s_id from suppliers AS s1 WHERE s1.s_city = 'Tianjin');
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希望本文所述对大家MySQL数据库计有所帮助。