I am running MySQL version 5.1.57
I have a HTML form where a user can insert a search-string. I create a $_SESSION on this string, then I run it in a MySQLquery. Something like this:
<?php
$sql = mysql_query ("SELECT
s.student_firstname, s.student_lastname
FROM students s
WHERE (
s.student_firstname LIKE '%$searchstring%' OR
s.student_lastname LIKE '%$searchstring%
)
AND s.isActive = '1' ");
?>
The problem is when a user is searching for multiple words. Then my query fails because it is trying to match the string against the values in either column.
I've read something about MySQL FULLTEXT indexing but as far as I understand, it only works on MyISAM tables(?). How can I be able to search for multiple words using the environment that I have?
I think you should split your searched string on space (" ") and insert each segment in your query, or in another query. For example :
$str = "word1 word2";
With that you search first for the whole string "word1 word2" and after you search in you database for "word1" and "word2".
With this solution you should handle a word ignore list, because words like "a, an, the, or, ..." shouldn't be seek ...
I'm not sure there is an other way with an innoDB table ... The best solution is obviously to use the "match against" command, but it's only available with a full text index under MyISAM.
Related
I am using MySql FullText indexing to search data from database.
Here is the query
$search_input_text = 'the_string_to_be_search';
$searchArray = explode(" ", $search_input_text);
$query="SELECT * FROM car_details
WHERE MATCH (car_trim) AGAINST ('";
foreach ($searchArray as $word) {
$query .= "+".$word."* ";
}
$query .= "' IN BOOLEAN MODE) LIMIT $start, $limit";
The query is executing fine but it has a bug, if you look at the column name you will find car_trim which is inside the MATCH() function. The column has only 3 different types of values in the database which are 'T5', 'T6' and 'T5 premier'.
When I type 'Premier' in the search bar and hit Enter, it fetches the results whose values contain the word 'Premier'. But when I type T5 or T6 , it returns an empty record. Please be sure that there are lots of records with car_trim='T5', car_trim='T6' or car_trim='T5 Premier'
I am not getting that what can be the problem with the strings T5 and T6.
MySQL has two key parameters when using full text search (and a few other important ones). The key parameters are the minimum word length and the stop words list. In short, MySQL ignores words that are less than 3 or 4 characters (depending on the storage engine) or that are in the stop word list.
Your examples ("T5" and "T6") are too short -- based on the parameter defaults.
Some other configuration parameters might be of interest, such as the maximum word length and the characters that are valid for words.
You can change the parameters for full text indexing and re-build the index.
Here is a good place to start in understanding this.
I am trying to make a search form with php, using the following query :
$this->images('`description`="'.db::escape($mysearch).'"');
It's working great, BUT it returns only the EXACT description that corresponds to $mysearch !
I would like that it returns all the descriptions that contains the keywords (1, 2 or 3) from the $mysearch field.
What is the exact SQL query ? I tried with :
'MATCH `description` AGAINST "'.db::escape($mysearch).'"'
But I get an error back:
You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near 'MATCH title AGAINST "mykeyword"' at line 1
The solution was :
'MATCH(title) AGAINST ("'.db::escape($keyword).'" IN BOOLEAN MODE)'
use explode:
http://php.net/manual/en/function.explode.php
on a space or comma as your delimiter, and then do a for each on the resulting array to add a line to the query for each string in that array.
For a pseudo example:
//input of the string
$input = "keyword1 keyword2 keyword3";
$inputArray = explode(" ",$input);
foreach ($inputArray as $keyword) {
$sql .= " OR tableName.ColName like '%$keyword%'";
}
obviously clean it up and validate the input, preferable use prepared statements etc (looks like you are using some sort of ORM?), and hopefully the description column is relatively short and has an index on its full content, otherwise the query will be very slow.
Update: I realize you were attempting the syntax to use a fulltext index. If you have a MyISAM table, or a new enough version of mysql that supports fulltext indexes on InnoDB tables, then you might want to skip this solution I have offered as it WILL become very slow once you have more records in teh table than will fit into memory / cache. Unfortunately, I have never used a fulltext index and cannot help you there. I am switching to using Zend_Search_Lucene vs the solution I listed above. (http://framework.zend.com/manual/en/zend.search.lucene.html)
I have a table, with not many rows, and neither many columns. I am doing a Full text search on 3 columns.
My code is
$search_input = trim($_GET['s']);
$search = mysql_real_escape_string($search_input);
$search = '+'.str_replace(' ', '* +', $search).'*';
$sql = "SELECT * FROM table WHERE
MATCH(def, pqr, xyz) AGAINST ('$search' IN BOOLEAN MODE)";
$result = mysql_query($sql);
I can correctly search for terms like abcdefgh, which are present as ... abcdefgh ....
But I am receiving empty set with search terms like abc, where in table entry is present something like abc-123, and also terms like abcdefghs. (notice this is plural of above)
Clearly I need to implement partial search, or something like that.
But how do I implement such a search? Any better way to do a entire table search on user input?
Do mention anything I am doing incorrectly.
EDIT : By adding * after each word, now I am able to also search for abcde, but above problems remains.
Do you mean you don't get results for 3 letter combinations? If so, you might be hitting the mysql index length (which is usually set to 3)
More info here - http://dev.mysql.com/doc/refman/5.1/en/fulltext-fine-tuning.html
I'm having trouble with the sql below. Basically I have rows that contains strings according to the format: 129&c=cars. I only want the digits part, e.g. 129. The sql query is:
$result = mysql_query("SELECT * FROM " . $db_table . " WHERE id LIKE '" . $id . "%'");
Why doesn't % work? I can't use %...% because it catches too much.
I would actually recommend using regular expressions fo the matching, but unfortunately, there is no way to capture the matching part with mysql. You will have to do the extraction in php. If you have an array containing all the results called $array:
$array = preg_replace('/^(\d+).*/', '$1', $array);
You can use the MySQL 'regexp' stuff in the WHERE clause to reduce the amount of data retrieved to just the rows you want. The basic for of your query would look like:
SELECT * FROM table WHERE field REGEXP '^$id&'
where $id is inserted by PHP and the data you want is always at the start of the field and followed by a &. If not, adjust the regex to suit, of course.
MySQL's regex engine can't do capturing, unfortunately, so you'll still have to do some parsing in PHP as soulmerge showed above, but with the 'where regexp' stuff in MySQL, you'll only have to deal with rows you know contain the data you want, not the entire table.
Using a query like this:
SELECT *
FROM mytable
WHERE id >= '0' COLLATE UTF8_BIN
AND id < ':' COLLATE UTF8_BIN
will return all strings that start with a digit and make your expression sargable, i. e. and index on id can be used.
This will make your query run faster.
I'm working on an 'advanced search' page on a site where you would enter a keyword such as 'I like apples' and it can search the database using the following options:
Find : With all the words, With the
exact phrase , With at least one of
the words, Without the words
I can take care of the 'Exact phrase' by:
SELECT * FROM myTable WHERE field='$keyword';
'At least one of the words' by:
SELECT * FROM myTable WHERE field LIKE '%$keyword%';//Let me know if this is the wrong approach
But its the 'With at least one of the words' and 'Without the words' that I'm stuck on.
Any suggestions on how to implement these two?
Edit: Regarding 'At least one word' it wouldn't be a good approach to use explode() to break the keywords into words, and run a loop to add
(field='$keywords') OR ($field='$keywords) (OR)....
Because there are some other AND/OR clauses in the query also and I'm not aware of the maximum number of clauses there can be.
I would suggest the use of MySQL FullText Search using this with the Boolean Full-Text Searches functionality you should be able to get your desired result.
Edit:
Requested example based on your requested conditions ("Its just one field and they can pick either of the 4 options (i.e 1 word, exact words, at least 1 word, without the term).")
I am assuming you are using php based on your initial post
<?php
$choice = $_POST['choice'];
$query = $_POST['query'];
if ($choice == "oneWord") {
//Not 100% sure what you mean by one word but this is the simplest form
//This assumes $query = a single word
$result = mysql_query("SELECT * FROM table WHERE MATCH (field) AGAINST ('{$query}' IN BOOLEAN MODE)");
} elseif ($choice == "exactWords") {
$result = mysql_query("SELECT * FROM table WHERE MATCH (field) AGAINST ('\"{$query}\"' IN BOOLEAN MODE)");
} elseif ($choice == "atLeastOneWord") {
//The default with no operators if given multiple words will return rows that contains at least one of the words
$result = mysql_query("SELECT * FROM table WHERE MATCH (field) AGAINST ('{$query}' IN BOOLEAN MODE)");
} elseif ($choice == "withoutTheTerm") {
$result = mysql_query("SELECT * FROM table WHERE MATCH (field) AGAINST ('-{$query}' IN BOOLEAN MODE)");
}
?>
hope this helps for full use of the operators in boolean matches see Boolean Full-Text Searches
You could use
With at least one of the words
SELECT * FROM myTable WHERE field LIKE '%$keyword%'
or field LIKE '%$keyword2%'
or field LIKE '%$keyword3%';
Without the word
SELECT * FROM myTable WHERE field NOT LIKE '%$keyword%';
I'm not sure you could easily do those search options in a naive manner as the other two.
It would be worth your while implementing a better search engine if you need to support those scenarios. A simple one that could probably get you by is something along these lines:
When an item is added to the database, it is split up into the individual words. At this point "common" words (the, a, etc...) are removed (probably based on a common_words table). The remaining words are added to a words table if they are not already present. There is then a link made between the word entry and the item entry.
When searching, it is then a case of getting the word ids from the word table and the appropriate lookup of item ids in the joining table.
Search is notoriously difficult to do well.
You should Consider using a third party search engine using something like Lucene or Sphider.
Giraffe and Re0sless pooseted 2 good answers.
notes:
"SELECT * " sucks... only select the columns that you need.
Re0sless puts a "OR" between keywords.
- you should eliminate common words (" ","i","am","and"..etc)
- mysql has a 8kb i belive limit on the size of the query, so for really long SELECTS you should slipt it into separate queries.
- try to eliminate duplicate keywords (if i search for "you know you like it" the SELECT should basically only search for "you" once and elimnate common words as "it")
Also try to use "LIKE" and "MATCH LIKE" (see mysql man page) it could do wonders for "fuzzy" searches