[PBN笔考题]mysql 一个简单查询中的group by 和 order by 的使用

具体我忘记了，大概内容差不多如下。

两张表，内容如下：

+--------+-------+------+| z_code | mgr   | pigs |+--------+-------+------+| 021    | zhang | 85   || 010    | wang  | 70   |+--------+-------+------+2 rows in set

查询最终结果

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+--------+------+-------+| z_code | city | mgr   |+--------+------+-------+| 010    | BJ   | wang  || 021    | HB   | zhang |+--------+------+-------+2 rows in set

A表

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+------+-------+------+| part | mgr   | pigs |+------+-------+------+| 001  | wang  |   20 || 002  | wang  |   50 || 011  | zhang |   49 || 012  | zhang |   36 |+------+-------+------+4 rows in set

?B表

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所用查询语句为：

select z_code, A.mgr mgr, sum(pigs) pigs from A, B where A.mgr = B.mgr group by A.mgr order by pigs desc;

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下面是建表和插入语句的SQL：

create database pig_store;use pig_store;create table A(    z_code varchar(8),    city varchar(4),    mgr varchar(16));create table B(    part varchar(8),    mgr varchar(16),    pigs int(5));insert into A values ( '010', 'BJ', 'wang'), ( '021', 'HB', 'zhang' );insert into B values ( '001', 'wang', 20 ), ( '002', 'wang', 50 ), ( '011', 'zhang', 49 ), ( '012', 'zhang', 36 );