Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 1747
  • Last Modified:

Using wildcards in MySQL fulltext searches

I'm using a MySQL database, and I have a table containing a text field. I was using a query to return all rows containing a string within the text field -

... WHERE desc like '%MSDN%'

But this is was too slow on a large table. I speeded this up by using a fulltext index on the 'desc' column in my table.
However, the equivalent fulltext search clause

... MATCH desc AGAINST ('MSDN')

returns rows matching

...w/MSDN Prem...

but not

...w/MSDNPrem...

I've tried modifying my fulltext search with wildcards i.e.

... MATCH desc AGAINST ('*MSDN*')

but this didn't work, I still didn't get the complete set of matches I expected. Does anyone know what the equivalent fulltext search pattern is, to return exactly the same resultset as my original query?
0
smartstream-stp
Asked:
smartstream-stp
  • 3
  • 2
1 Solution
 
Guy Hengel [angelIII / a3]Billing EngineerCommented:
what about:
... MATCH desc AGAINST ('MSDN*')

Open in new window

0
 
smartstream-stpAuthor Commented:
Unfortunately that doesn't work. 'MSDN*' does not return rows containing '...w/MSDNPrem...'
0
 
Guy Hengel [angelIII / a3]Billing EngineerCommented:
first you cannot use *something in FT...

so, I am not sure, but maybe / is not a word breaker....
http://dev.mysql.com/doc/refman/5.0/en/fulltext-fine-tuning.html

#If you want to change the set of characters that are considered word characters, you can do so in two ways. Suppose that you want to treat the hyphen character ('-') as a word character. Use either of these methods:
 
    *    Modify the MySQL source: In myisam/ftdefs.h, see the true_word_char() and misc_word_char() macros. Add '-' to one of those macros and recompile MySQL.
 
    *    Modify a character set file: This requires no recompilation. The true_word_char() macro uses a character type table to distinguish letters and numbers from other characters. . You can edit the <ctype><map> contents in one of the character set XML files to specify that '-' is a letter. Then use the given character set for your FULLTEXT indexes.
 
After making the modification, you must rebuild the indexes for each table that contains any FULLTEXT indexes.

Open in new window

0
Fill in the form and get your FREE NFR key NOW!

Veeam is happy to provide a FREE NFR server license to certified engineers, trainers, and bloggers.  It allows for the non‑production use of Veeam Agent for Microsoft Windows. This license is valid for five workstations and two servers.

 
jericotolentinoCommented:
Try if MySQL boolean search works for you:

SELECT *,MATCH(desc) AGAINST ('*MSDN*' IN BOOLEAN MODE) AS score FROM search WHERE MATCH(desc) AGAINST ('*MSDN*' IN BOOLEAN MODE);

It requires that you're using MyISAM and the indexes you're searching are of type varchar or text.

More info is available here:
http://dev.mysql.com/doc/refman/5.0/en/fulltext-search.html
0
 
smartstream-stpAuthor Commented:
If '/' isn't a word breaker, then how is 'w/MSDN Prem' matched, but not 'w/MSDNPrem' ?

I don't think fulltext indexing is going to be 100% reliable for me, as it relies on the text field being split into words. In my case I can't guarantee this. I don't think there is any direct equivalent for 'WHERE desc LIKE '%MSDN%' i.e. matching an aribitrary string within a text field.

0
 
smartstream-stpAuthor Commented:
jericotolentino's suggestion worked much better, but didn't match a field value of

VStudio Team Ed Sft Test AllLngLic/SAOLVNL1YRAcqY1wMSDNPrmAdPrdPrtnrOnly
0

Featured Post

Fill in the form and get your FREE NFR key NOW!

Veeam is happy to provide a FREE NFR server license to certified engineers, trainers, and bloggers.  It allows for the non‑production use of Veeam Agent for Microsoft Windows. This license is valid for five workstations and two servers.

  • 3
  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now