SQL中的CASE语句可以完成很多有意义的事情，通过这个小文儿给大家展示一下使用CASE语句做一个自我介绍。

1.创建实验表T，并初始化数据。
sec@ora10g> create table t (x varchar2(8));
sec@ora10g> insert into t values ('Andy');
sec@ora10g> insert into t values ('HOU');
sec@ora10g> insert into t values ('Anna');
sec@ora10g> insert into t values ('TuTu');
sec@ora10g> insert into t values ('Secooler');
sec@ora10g> commit;

2.简单查看一下T表中的数据
sec@ora10g> select * from t;

X
--------
Andy
HOU
Anna
TuTu
Secooler

3.现在是使用CASE的自我介绍时间
sec@ora10g> select x, case
2               when x = 'Andy' then '<-- It''s my English name.'
3               when x = 'HOU' then '<-- It''s my family name.'
4               when x = 'Anna' then '<-- She is my wife.'
5               when x = 'TuTu' then '<-- He is my son. He is one year old now.'
6               when x = 'Secooler' then '<-- Yes, It''s me.'
7               else null
8            end
9               introduce
10    from t
11 /

X        INTRODUCE
-------- -----------------------------------------
Andy     <-- It's my English name.
HOU      <-- It's my family name.
Anna     <-- She is my wife.
TuTu     <-- He is my son. He is one year old now.
Secooler <-- Yes, It's me.

4.有关CASE的官方文档位置（10gR2）
http://download.oracle.com/docs/cd/B19306_01/appdev.102/b14261/case_statement.htm#i36967

5.小结
“小CASE，大用途”。在实现简单分支语句功能上面CASE有它自身的优势。

Good luck.

secooler
09.12.15

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【SQL】小CASE

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