I am attempting a fulltext search in mysql. I expect that when I pass in a string, I will receive ranked by relevancy when I use [Natural Language Mode]mysql - fulltext index - what is natural language mode .
Here is how I created the index: CREATE FULLTEXT INDEX item_name ON list_items(name);
When I use LIKE, I receive results, except I want to order them by relevancy. Hence, the fulltext search.
Here is the query I have using LIKE: SELECT name FROM list_items WHERE name LIKE "%carro%";
Which results in Carrots, Carrots, Carrots etc.
Here is the query I have attempting the MATCH search: SELECT name FROM list_items WHERE MATCH(name) AGAINST('carro' IN NATURAL LANGUAGE MODE); Which returns no results.
I am basing my query on the selected answer on this post: Order SQL by strongest LIKE?
And this page: https://www.w3resource.com/mysql/mysql-full-text-search-functions.php
Even when I run the query without Natural Language Mode or even in Boolean Mode, I don't get any results. What am I missing?
You seem to want to use * as a wildcard. For that you need to use "boolean" mode rather than "natural language". So, this might do what you want:
SELECT name
FROM list_items
WHERE MATCH(name) AGAINST('carro*' IN BOOLEAN MODE)
This still produces a relevance ranking, although it might not be exactly the same as natural language mode.
Also note that this will get matches such as "carrouse".
I don't think that MySQL supports synonym lists for full text search, so this is tricky to avoid (although like filtering along with the full text filtering might suffice).
Related
Stemming Words in MySQL
For e.g. the user might search for "testing", "tested" or "tests". All these words are related to each other because the base word "test" is common in all of them.
Is there a way to get such result or function?
MySQL Full-Text Search
Historically, full-text searches were supported in MyISAM engines. After version 5.6, MySQL also supported full-text searches in InnoDB storage engines. This has been great news, since it enables developers to benefit from InnoDB’s referential integrity, ability to perform transactions, and row level locks.
There are basically two approaches to full-text searches in MySQL: natural language and boolean mode. (A third option augments the natural language search with a second expansion query.)
The main difference between the natural and boolean modes is that the boolean allows certain operators as part of the search. For instance, boolean operators can be used if a word has greater relevance than others in the query or if a specific word should be present in the results, etc. It’s worth noticing that in both cases, results can be sorted by the relevance computed by MySQL during the search.
The best fit for our problem was to use InnoDb full-text searches in boolean mode. Why?
We had little time to implement the search function.
At this point, we had no big data to crunch nor a massive load to require something like Elasticsearch or Sphinx.
We used shared hosting that doesn’t support Elasticsearch or Sphinx and the hardware was pretty limited at this stage.
While we wanted word stemming in our search function, it wasn’t a deal breaker: we could implement it (within constraints) by way of some simple PHP coding and data denormalization
Full-text searches in boolean mode can search words with wildcards (for the word stemming) and sort the results based on relevance.
In the Normalized Vertabelo Model
Let’s see how a simple search would work. We’ll create a sample table first:
CREATE TABLE artists (
id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL,bio text NOT NULL, CONSTRAINT artists_pk PRIMARY KEY (id)
)ENGINE InnoDB;
CREATE FULLTEXT INDEX artists_idx_1 ON artists (name);
In natural language mode
You can insert some sample data and start testing. (It would be good to add it to your sample dataset.) For instance, we’ll try searching for Michael Jackson:
SELECT
*
FROM
artists
WHERE
MATCH (artists.name) AGAINST ('Michael Jackson' IN NATURAL LANGUAGE MODE)
This query will find records that match the search terms and will sort matching records by relevance; the better the match, the more relevant it is and the higher the result will appear in the list.
In boolean mode
We can perform the same search in boolean mode. If we don’t apply any operators to our query, the only difference will be that results are not sorted by relevance:
SELECT
*
FROM
artists
WHERE
MATCH (artists.name) AGAINST ('Michael Jackson' IN BOOLEAN MODE)
The wildcard operator in boolean mode
Since we want to search stemmed and partial words, we will need the wildcard operator (*). This operator can be used in boolean mode searches, which is why we chose that mode.
So, let’s unleash the power of boolean search and try searching for part of the artist’s name. We’ll use the wildcard operator to match any artist whose name starts with ‘Mich’:
SELECT
*
FROM
artists
WHERE
MATCH (name) AGAINST ('Mich*' IN BOOLEAN MODE)
Stemming Words in MySQL
For e.g. the user might search for "testing", "tested" or "tests". All these words are related to each other because the base word "test" is common in all of them.
Is there a way to get such result or function?
MySQL Full-Text Search
Historically, full-text searches were supported in MyISAM engines. After version 5.6, MySQL also supported full-text searches in InnoDB storage engines. This has been great news, since it enables developers to benefit from InnoDB’s referential integrity, ability to perform transactions, and row level locks.
There are basically two approaches to full-text searches in MySQL: natural language and boolean mode. (A third option augments the natural language search with a second expansion query.)
The main difference between the natural and boolean modes is that the boolean allows certain operators as part of the search. For instance, boolean operators can be used if a word has greater relevance than others in the query or if a specific word should be present in the results, etc. It’s worth noticing that in both cases, results can be sorted by the relevance computed by MySQL during the search.
The best fit for our problem was to use InnoDb full-text searches in boolean mode. Why?
We had little time to implement the search function.
At this point, we had no big data to crunch nor a massive load to require something like Elasticsearch or Sphinx.
We used shared hosting that doesn’t support Elasticsearch or Sphinx and the hardware was pretty limited at this stage.
While we wanted word stemming in our search function, it wasn’t a deal breaker: we could implement it (within constraints) by way of some simple PHP coding and data denormalization
Full-text searches in boolean mode can search words with wildcards (for the word stemming) and sort the results based on relevance.
In the Normalized Vertabelo Model
Let’s see how a simple search would work. We’ll create a sample table first:
CREATE TABLE artists (
id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL,bio text NOT NULL, CONSTRAINT artists_pk PRIMARY KEY (id)
)ENGINE InnoDB;
CREATE FULLTEXT INDEX artists_idx_1 ON artists (name);
In natural language mode
You can insert some sample data and start testing. (It would be good to add it to your sample dataset.) For instance, we’ll try searching for Michael Jackson:
SELECT
*
FROM
artists
WHERE
MATCH (artists.name) AGAINST ('Michael Jackson' IN NATURAL LANGUAGE MODE)
This query will find records that match the search terms and will sort matching records by relevance; the better the match, the more relevant it is and the higher the result will appear in the list.
In boolean mode
We can perform the same search in boolean mode. If we don’t apply any operators to our query, the only difference will be that results are not sorted by relevance:
SELECT
*
FROM
artists
WHERE
MATCH (artists.name) AGAINST ('Michael Jackson' IN BOOLEAN MODE)
The wildcard operator in boolean mode
Since we want to search stemmed and partial words, we will need the wildcard operator (*). This operator can be used in boolean mode searches, which is why we chose that mode.
So, let’s unleash the power of boolean search and try searching for part of the artist’s name. We’ll use the wildcard operator to match any artist whose name starts with ‘Mich’:
SELECT
*
FROM
artists
WHERE
MATCH (name) AGAINST ('Mich*' IN BOOLEAN MODE)
search term=['ISBN number on site']
the variable(column): sentence, in MySQL table. It consist many different sentence.
the sentence I want to look for is
"The AutoLink feature comes with Google's latest toolbar and provides links in a webpage to Amazon.com if it finds a book's ISBN number on the site."
However, When I use the following statement:
SELECT * FROM testtable
where Sentence like "%ISBN number on site%" ;
I am not able to get the result. This is because the search term("ISBN number on site") is lack of one word("the") compare with the sentence.
How to change my statement in order to get the sentence I want? thanks.
Assume that We do not change the search term=['ISBN number on site']
This is not a simple question. Your best bet is to use some type of fulltext search. Fulltext search can be configured to have stopwords (words that are omitted from search - like the word the) and can have a minimum word length limit as well (words with less than certain characters long are also omitted from the search.
However, if you simply use
SELECT * FROM testtable
WHERE MATCH (sentence)
AGAINST ('ISBN number on site');
Then MySQL will return not just the record with the value you were looking for, but the records that have some of the words only, and in different order. The one you showed will probably be one of the highest ranking one, but there is no guarantee that it will be highest ranked one.
You may want to use Boolean fulltext search and prepend + to every search word to force MySQL to return those records only that have all the search words present:
SELECT * FROM testtable
WHERE MATCH (sentence)
AGAINST ('+ISBN +number +on +site' IN BOOLEAN MODE);
But, on should either be a stopword (it is on the default stipword lists) or should be shorter that the minimum word length, so should be omitted from the search expression (you will not get back any results):
SELECT * FROM testtable
WHERE MATCH (sentence)
AGAINST ('+ISBN +number +site' IN BOOLEAN MODE);
I know that this requires alteration of the search expression, however this will get you the best results using MySQL's built-in functionality.
The alternative is to use other fulltext search engines, such as sphinx to perform the search for you.
Try:
SELECT * FROM testtable where Sentence like '%ISBN number on%site%' ;
The wildcard can go in the middle of a string too.
I would like to use the position/index found by the Match...Against fulltext search in mysql to return some text before and after the match in the field. Is this possible? In all the examples I have seen, the Match...Against returns a score in the select instead of a location or position in the text field of which is being searched.
SELECT
random_field,
MATCH ($search_fields)
AGAINST ('".mysql_real_escape_string(trim($keywords))."' IN BOOLEAN MODE)
AS score
FROM indexed_sites
WHERE
MATCH ($search_fields)
AGAINST ('".mysql_real_escape_string($keywords)."' IN BOOLEAN MODE)
ORDER BY score DESC;
This will give me a field and a score...but I would like an index/position instead of (or along side) a score.
Fulltext searching is a scoring function. its not a search for occurrence function. In other words the highest scoring result may not have a starting position for the match. As it may be a combination of weighted results of different matches within the text. if you include query expansion the search for word/s may not even appear in the result!
http://dev.mysql.com/doc/refman/5.0/en/fulltext-query-expansion.html
I hope that makes some sense.
Anyway your best bet is to take the results and then use some text searching function to find the first occurrence of the first matching word. My guess is that would be best suited to a text processing language like perl or a more general language like php or what ever language you are using to run the query.
DC
in the match - against am getting the correct results, there is no problem but the thing i want is the result combination.
Like for "computer graphics" i am getting results for "+computer +graphics" as "computer" alone results and "computer graphics" results and "graphics" results and etc.
Here i want "computer graphics" results first then the other single word match results. How can i bring those first. Help me some one please
you should order by relevance: search for the same query you use in WHERE, call is RELEVANCE and then order by that field.
SELECT MATCH('...') AGAINST ('...') as Relevance
FROM table WHERE MATCH('...') AGAINST('...' IN
BOOLEAN MODE)
ORDER BY Relevance DESC
This can't be done in MySQL fulltext search without a bit of hoop jumping.
You basically need to run the search twice to get your desired results. First, run a boolean fulltext search using double quotes to enclose the exact phrase being searched for. The double quotes in boolean mode will return exact matches only. Once you have those results, then your normal natural-language search. It's the normal, natural language search that is giving you trouble with partial matches. You'll need to manually combine the two search results.
While MySQL fulltext is decent for simple searching needs, it's not a great search solution. Consider something with more power, like Sphinx, Solr / Lucene, or even something like ElasticSearch.
Assuming we're talking about a full-text index:
... ORDER BY MATCH('computer graphics') AGAINST (some,columns) DESC;
Entries in table
what is computer?
what is graphics on computer?
what is computer graphics?
what is graphics?
QUERY : select *,MATCH(field1,field2) AGAINST ("+computer +graphics" IN BOOLEAN MODE) as results from $table where MATCH(field1,field2) AGAINST ("+computer +graphics" IN BOOLEAN MODE) ORDER BY results ASC
IT RETURNS exact results some where in the middle and others are first.
Like
what is computer graphics?
what is graphics on computer?
what is computer?
what is graphics?
How it can be corrected....