Is this a like query bug?

Question

Oracle
version:9.2.0.1
character:AMERICAN_AMERICA.US7ASCII
The sql is like this , There is a chinese character '仙' in the where clause:
select * from ta where mc like '%仙%';
but the result records don't have the character '仙' in the colomn mc.
I tried this sql in oracle10.2.0.1, the result is still wrong.
Why?
How could I solve this problem?
anyone could help,thanks very much!
Edited by: user511131 on 2008-10-26 上午12:43
Edited by: user511131 on 2008-10-26 上午1:22

Answer 1

<h3>Unicode String Literals</h3>
<p>
You can input <a name="sthref842" title="sthref842"></a><a name="sthref843" title="sthref843"></a>Unicode string literals in SQL and PL/SQL as follows:
</p>
<ul>
<li>
<p>
     Put a prefix <code>N</code> before a string literal that is enclosed with single quote marks. This explicitly indicates that the following string literal is an <code>NCHAR</code> string literal. For example, <code>N'r&eacute;sum&eacute;'</code> is an <code>NCHAR</code> string literal. For information about limitations of this method, see NCHAR String Literal Replacement.
</p>
</li>
<li>
<p>
     Use the <code><a name="sthref844" title="sthref844"></a><a name="sthref845" title="sthref845"></a>NCHR(</code><code>n</code><code>)</code> SQL function, which returns a unit of character code in the national character set, which is AL16UTF16 or UTF8. The result of concatenating several <code>NCHR(</code><code>n</code><code>)</code> functions is <code>NVARCHAR2</code> data. In this way, you can bypass the client and server character set conversions and create an <code>NVARCHAR2</code> string directly. For example, <code>NCHR(32)</code> represents a blank character.
</p>
<p>
     Because <code>NCHR(</code><code>n</code><code>)</code> is associated with the national character set, portability of the resulting value is limited to applications that run with the same national character set. If this is a concern, then use the <code>UNISTR</code> function to remove portability limitations.
</p>
</li>
<li>
<p>
     Use the <code><a name="sthref846" title="sthref846"></a><a name="sthref847" title="sthref847"></a>UNISTR</code>('<code>string'</code>) SQL function. <code>UNISTR</code>('<code>string'</code>) converts a string to the national character set. To ensure portability and to preserve data, include only ASCII characters and Unicode encoding in the following form: <code>\xxxx</code>, where <code>xxxx</code> is the hexadecimal value of a character code value in UTF-16 encoding format. For example, <code>UNISTR('G\0061ry')</code> represents <code>'Gary'</code>. The ASCII characters are converted to the database character set and then to the national character set. The Unicode encoding is converted directly to the national character set.
</p>
</li>
</ul>
<p>
To solve this problem,,should I use UNISTR to convert the character to unicode,
how to ...
I have no idea?:|
</p>