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POStrange behavior of LENGTH command - ORACLE
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copied!<p>I've encountered here an inusited situation that I couldn't understand. Nor the documentation of the functions that I will write about has something to light up this thing.</p> <p>I've a table with a field <code>titulo varchar2(55)</code>. I'm in Brazil, some of the characters in this field has accents and my goal is to create a similar field without the accents (replaced by the original character as this <code>á</code> became <code>a</code> and so on.).</p> <p>I could use a bunch of functions to do that as <code>replace</code>, <code>translate</code> and others but I find over the internet one that seams to be more elegant, then I use it. That is where the problem came.</p> <p>My update code is like:</p> <pre><code>update myTable set TITULO_URL = replace( utl_raw.cast_to_varchar2( nlssort(titulo, 'nls_sort=binary_ai') ) ,' ','_'); </code></pre> <p>As I said the goal is to transform every accented character in its equivalent without the accent plus the spaces character for an <code>_</code></p> <p>Then I got this error:</p> <pre><code>ORA-12899: value too large for column "mySchem"."myTable"."TITULO_URL" (actual: 56, maximum: 55) </code></pre> <p>And at first I though maybe those functions are adding some character, let me checkit. I did a select command to get me a row where <code>titulo</code> has 55 characters. </p> <pre><code>select titulo from myTable where length(titulo) = 55 </code></pre> <p>Then I choose a row to do some tests, the row that I choose has this value: <code>'FGHJTÓRYO DE YHJKS DA DGHQÇÃA DE ASGA XCVBGL EASDEÔNASD'</code> (I did change it bit to preserve the data, but the result is the same)</p> <p>When i do the following select statement that things became weird:</p> <pre><code>select a, length(a), b, length(b) from ( select 'FGHJTÓRYO DE YHJKS DA DGHQÇÃA DE ASGA XCVBGL EASDEÔNASD' a, replace( utl_raw.cast_to_varchar2( nlssort('FGHJTÓRYO DE YHJKS DA DGHQÇÃA DE ASGA XCVBGL EASDEÔNASD', 'nls_sort=binary_ai') ) ,' ','_') b from dual ) </code></pre> <p>The result for this sql is (i will put the values one down other for better visualization):</p> <pre><code> a LENGTH(a) FGHJTÓRYO DE YHJKS DA DGHQÇÃA DE ASGA XCVBGL EASDEÔNASD 55 b LENGTH(b) fghjtoryo_de_yhjks_da_dghqcaa_de_asga_xcvbgl_easdeonasd 56 </code></pre> <p>Comparing the two strings one above other there is no difference in size:</p> <pre><code>FGHJTÓRYO DE YHJKS DA DGHQÇÃA DE ASGA XCVBGL EASDEÔNASD fghjtoryo_de_yhjks_da_dghqcaa_de_asga_xcvbgl_easdeonasd </code></pre> <p>I've tested this query on Toad, PLSQL Developer and SQLPLUSW all with the same result. So my question is <strong>Where this LENGTH(b)=56 came from</strong>? I know that it can be something with character set, but I couldn't figure out why. I even tested with the <code>trim</code> command and the result is the same. </p> <p>Another tests that i did</p> <ul> <li><code>substr(b, 1,55)</code> the result was the same text as above</li> <li><code>lenght(trim(b))</code> the result was 56</li> <li><code>substr(b,56)</code> the result was empty (no null, no space, just empty)</li> </ul> <p>Suggested by @Sebas:</p> <ul> <li><code>LENGTHB(b)</code> the result was 56</li> <li><code>ASCII(substr(b,56))</code></li> </ul> <p>So, again: <strong>Where this LENGTH(b)=56 came from</strong>?</p> <p>Sorry for the long post and thank you for the ones who get down here (read everything). An thanks for the ones who doesn't read anyway :)</p> <p>Best regards</p>

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