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');
希望本文所述对大家MySQL数据库计有所帮助。