SQL - 条件ロジック(検索case式)

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11章(条件ロジック),　11.4(練習問題)11-1を解いてみる。

11-1.

SQL文(TextWrangler)

select emp_id,
  case
    when title like  "%President" or 
      title = "Treasurer" or
      title = "Loan Manager" then "Management"
    when title  = "Operations%" or
      title like "%Teller%" then "Operations"
    else "Unknown"
  end title
from employee;

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 17
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> select emp_id,
    ->   case
    ->     when title like  "%President" or 
    ->       title = "Treasurer" or
    ->       title = "Loan Manager" then "Management"
    ->     when title  = "Operations%" or
    ->       title like "%Teller%" then "Operations"
    ->     else "Unknown"
    ->   end title
    -> from employee;
+--------+------------+
| emp_id | title      |
+--------+------------+
|      1 | Management |
|      2 | Management |
|      3 | Management |
|      4 | Unknown    |
|      5 | Management |
|      6 | Operations |
|      7 | Operations |
|      8 | Operations |
|      9 | Operations |
|     10 | Operations |
|     11 | Operations |
|     12 | Operations |
|     13 | Operations |
|     14 | Operations |
|     15 | Operations |
|     16 | Operations |
|     17 | Operations |
|     18 | Operations |
+--------+------------+
18 rows in set (0.00 sec)

mysql> quit
Bye
$