SQL - サブクエリ(式ジェネレータとしてのサブクエリ)

初めてのSQL
Alan Beaulieu (著)

開発環境

• OS: OS X Lion - Apple
• データベース言語: SQL
• リレーショナルデータベース: MySQL

『初めてのSQL』(Alan Beaulieu 著、株式会社クイープ 翻訳、オライリー・ジャパン、2006年、ISBN4-87311-281-8) の9章(サブクエリ),　9.7(練習問題)9-4を解いてみる。

9-4.

入出力結果(Terminal)

$ mysql -u lrngsql -p bank
Enter password: 
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.5.24 MySQL Community Server (GPL)

Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> desc employee;
+--------------------+----------------------+------+-----+---------+----------------+
| Field              | Type                 | Null | Key | Default | Extra          |
+--------------------+----------------------+------+-----+---------+----------------+
| emp_id             | smallint(5) unsigned | NO   | PRI | NULL    | auto_increment |
| fname              | varchar(20)          | NO   |     | NULL    |                |
| lname              | varchar(20)          | NO   |     | NULL    |                |
| start_date         | date                 | NO   |     | NULL    |                |
| end_date           | date                 | YES  |     | NULL    |                |
| superior_emp_id    | smallint(5) unsigned | YES  | MUL | NULL    |                |
| dept_id            | smallint(5) unsigned | YES  | MUL | NULL    |                |
| title              | varchar(20)          | YES  |     | NULL    |                |
| assigned_branch_id | smallint(5) unsigned | YES  | MUL | NULL    |                |
+--------------------+----------------------+------+-----+---------+----------------+
9 rows in set (0.05 sec)

mysql> show tables;
+----------------+
| Tables_in_bank |
+----------------+
| account        |
| branch         |
| business       |
| customer       |
| department     |
| employee       |
| individual     |
| officer        |
| product        |
| product_type   |
| tmp            |
| transaction    |
+----------------+
12 rows in set (0.00 sec)

mysql> desc department;
+---------+----------------------+------+-----+---------+----------------+
| Field   | Type                 | Null | Key | Default | Extra          |
+---------+----------------------+------+-----+---------+----------------+
| dept_id | smallint(5) unsigned | NO   | PRI | NULL    | auto_increment |
| name    | varchar(20)          | NO   |     | NULL    |                |
+---------+----------------------+------+-----+---------+----------------+
2 rows in set (0.03 sec)

mysql> desc branch;
+-----------+----------------------+------+-----+---------+----------------+
| Field     | Type                 | Null | Key | Default | Extra          |
+-----------+----------------------+------+-----+---------+----------------+
| branch_id | smallint(5) unsigned | NO   | PRI | NULL    | auto_increment |
| name      | varchar(20)          | NO   |     | NULL    |                |
| address   | varchar(30)          | YES  |     | NULL    |                |
| city      | varchar(20)          | YES  |     | NULL    |                |
| state     | varchar(2)           | YES  |     | NULL    |                |
| zip       | varchar(12)          | YES  |     | NULL    |                |
+-----------+----------------------+------+-----+---------+----------------+
6 rows in set (0.00 sec)

mysql> select e.emp_id,e.fname,e.lname,(
    -> select d.name from department d
    -> where e.dept_id = d.dept_id) dept_name,(
    -> select b.name from branch b
    -> where e.assigned_branch_id = d.branch_id) branch_name
    -> from employee e;
ERROR 1054 (42S22): Unknown column 'd.branch_id' in 'where clause'
mysql> select e.emp_id,e.fname,e.lname,(
    -> select d.name from department d
    -> where e.dept_id = d.dept_id) dept_name,(
    -> select b.name from branch b
    -> where e.assigned_branch_id = b.branch_id) branch_name
    -> from employee e;
+--------+----------+-----------+----------------+---------------+
| emp_id | fname    | lname     | dept_name      | branch_name   |
+--------+----------+-----------+----------------+---------------+
|      1 | Michael  | Smith     | Administration | Headquarters  |
|      2 | Susan    | Barker    | Administration | Headquarters  |
|      3 | Robert   | Tyler     | Administration | Headquarters  |
|      4 | Susan    | Hawthorne | Operations     | Headquarters  |
|      5 | John     | Gooding   | Loans          | Headquarters  |
|      6 | Helen    | Fleming   | Operations     | Headquarters  |
|      7 | Chris    | Tucker    | Operations     | Headquarters  |
|      8 | Sarah    | Parker    | Operations     | Headquarters  |
|      9 | Jane     | Grossman  | Operations     | Headquarters  |
|     10 | Paula    | Roberts   | Operations     | Woburn Branch |
|     11 | Thomas   | Ziegler   | Operations     | Woburn Branch |
|     12 | Samantha | Jameson   | Operations     | Woburn Branch |
|     13 | John     | Blake     | Operations     | Quincy Branch |
|     14 | Cindy    | Mason     | Operations     | Quincy Branch |
|     15 | Frank    | Portman   | Operations     | Quincy Branch |
|     16 | Theresa  | Markham   | Operations     | So. NH Branch |
|     17 | Beth     | Fowler    | Operations     | So. NH Branch |
|     18 | Rick     | Tulman    | Operations     | So. NH Branch |
+--------+----------+-----------+----------------+---------------+
18 rows in set (0.15 sec)

mysql> quit;
Bye
$