I have a problem with FULLTEXT search in MySql.
I create query:
SELECT searchTag, MATCH (searchTag) AGAINST ('after party') as score FROM post WHERE MATCH (searchTag) AGAINST ('after party') ORDER BY score DESC
Its result:
1. we,like,to,party 3.6987853050231934
2. f,w,g,party 3.6987853050231934
3. after,party,tooka 3.657205581665039
Why number 3 have lower score if it have two words searching?
after is a stop word. It is ignored by a FULLTEXT MATCH query.
Basically, the word "after" is so common in the English language that including it in a query is semantically meaningless.
Think of it this way: imagine a query against the word "a". There are so many sentences which use the word "a", that a match against them really won't provide you with anything useful.
In this post, all of the sentences reference the word "a".
Related
SELECT user_id, user_name.fullname, live, likes,
MATCH (fullname, email, live) AGAINST (:search_I IN BOOLEAN MODE) AS relevance
FROM profile LEFT JOIN user_name ON user_id=user_id
WHERE MATCH (fullname, email, live) AGAINST (:search_II IN BOOLEAN MODE)
ORDER BY relevance DESC
bindValue(':search_I', $search...);
bindValue(':search_II', $search...);//PDO can't use same one twice
I have a query use FULL TEXT search, I need to order by the closest match on top.
However this query is not working, It didn't order anything.
I did a testing, search 123#hotmail.com
2 rows in my db, abc#hotmail.com & 123#hotmail.com
It return 2 rows but didn't put the closest match on top(123#hotmail.com)
anyone know where is the problems?
By default MySQL full text search has a minimum word length of 3 (see here).
So, your example of '123#hotmail.com' is only matching on 'hotmail' and the two are equivalent.
You can change the default (and rebuild the index). But, I'd suggest that you do testing with 'abcd#hotmail.com' instead.
EDIT:
The definition of a word is buried a bit in the documentation:
The MySQL FULLTEXT implementation regards any sequence of true word
characters (letters, digits, and underscores) as a word. That sequence
may also contain apostrophes (“'”), but not more than one in a row.
This means that aaa'bbb is regarded as one word, but aaa''bbb is
regarded as two words. Apostrophes at the beginning or the end of a
word are stripped by the FULLTEXT parser; 'aaa'bbb' would be parsed as
aaa'bbb.
Because of the where clause, you can see that there is a match to both email addresses. That match would have to be on 'hotmail'. The 'com' and email name get chopped off because of the default minimum word length.
I've been loking into Mysql's Match Against search. The results are strange. For example, if I have a table attribute with an entry "education" and do a search (using match against) for "edu" then it finds it. But if i search for "educ" no results are returned. All the way up to "educatio" does not return results. So it only matches whole words, or if 3 letters or less match in a word.
Is there a way to improve it so that results are returned when a search term is a subset of a word in the attribute? E.g. using the example above, searching "educat" would return rows containing "Education"
You can do exactly what you want by matching IN BOOLEAN MODE and using the * operator.
For example:
... MATCH(thing) AGAINST ('+educat*' IN BOOLEAN MODE)...
The + tells the match to include only the values of thing that contain the match term, which in this case is all indexed values beginning with "educat" (see here for how Boolean mode works in detail).
As an aside, Fulltext search in MySQL does not index words of 3 or fewer characters by default, so I suspect your match with "edu" is not working the way you think. Look at the value of your ft_min_word_len variable to see if that's the case.
you can use the mark %a (a=your word or letter)that search any word that start with the same word or letter
you can use %a% that search part of the word that the start and/or in the middle of the word
and the last one you can use a% that ends with the word or letter
I've setup a fulltext search to listen on the title and description columns for my blog articles table in MySQL. The SQL that I use to search the table is as follows:
SELECT title,description,publish_date FROM table WHERE MATCH(title,description) AGAINST('cats','dogs') ORDER BY publish_date DESC LIMIT 100
This works (for 'dogs' and 'cats'), but when I use the singular ('dog' or 'cat') then I find no results. Not sure why this is going on, I've tried different variations like "+dog, +cat" and tried including IN BOOLEAN MODE as well ... Nothing works. And Yes I am sure that there are other words in the description column that are "dog" and "cat" as well as their plural versions.
How can I get singular words to work with MySQL?
The default minimum word length for full-text searches is 4 characters.
You'll need to change that in the server configuration. See here for some info on how to do it.
why don't you try something like this:
SELECT title,description,publish_date, MATCH(title,description) AGAINST('search') AS score FROM table WHERE MATCH(title,description) AGAINST('seacrh') ORDER BY score LIMIT 100;
maybe this will help but will not work propertly with one word
I'm pretty new to MySQL full-text searches and I ran into this problem today:
My company table has a record with "e-magazine AG" in the name column. I have a full-text index on the name column.
When I execute this query the record is not found:
SELECT id, name FROM company WHERE MATCH(name) AGAINST('+"e-magazi"*' IN BOOLEAN MODE);
I need to work with quotes because of the dash and to use the wildcard because I implement a "search as you type" functionality.
When I search for the whole term "e-magazine AG", the record is found.
Any ideas what I'm doing wrong here? I read about adding the dash to the list of word characters (config update needed) but I'm searching for a way to do this programmatically.
This clause
MATCH(name) AGAINST('+"e-magazi"*' IN BOOLEAN MODE);
Will search for a AND "e" AND NOT "magazi"; i.e. the - inside "e-magazi" will be interpreted as a not even though it is inside quotation marks.
For this reason it will not work as expected.
A solution is to apply an extra having clause with a LIKE.
I know this having is slow, but it will only be applied to the results of the match, so not too many rows should be involved.
I suggest something like:
SELECT id, name
FROM company
WHERE MATCH(name) AGAINST('magazine' IN BOOLEAN MODE)
HAVING name LIKE '%e-magazi%';
MySQL fulltext treats the word e-magazine in a text as a phrase and not as a word. Because of that it results the two words e and magazine. And while it builds the search index it does not add the e to the index because of the ft_min_word_len (default is 4 chars).
The same length limitation is used for the search query. That is the reason why a search for e-magazine returns exactly the same results as a-magazine because a and - is fully ignored.
But now you want to find the exact phrase e-magazine. By that you use the quotes and that is the complete correct way to find phrases, but MySQL does not support operators for phrases, only for words:
https://dev.mysql.com/doc/refman/5.7/en/fulltext-boolean.html
With this modifier, certain characters have special meaning at the beginning or end of words in the search string
Some people would suggest to use the following query:
SELECT id, name
FROM company
WHERE MATCH(name) AGAINST('e-magazi*' IN BOOLEAN MODE)
HAVING name LIKE 'e-magazi%';
As I said MySQL ignores the e- and searches for the wildcard word magazi*. After those results are optained it uses HAVING to aditionally filter the results for e-magazi* including the e-. By that you will find the phrase e-magazine AG. Of course HAVING is only needed if the search phrase contains the wildcard operator and you should never use quotes. This operator is used by your user and not you!
Note: As long you do not surround the search phrase with % it will find only fields that start with that word. And you do not want to surround it, because it would find bee-magazine as well. So maybe you need an additional OR HAVING name LIKE ' %e-magazi%' OR HAVING NAME LIKE '\\n%e-magazi%' to make it usable inside of texts.
Trick
But finally I prefer a trick so HAVING isn't needed at all:
If you add texts to your database table, add them additionally to a separate fulltext indexed column and replace words like up-to-date with up-to-date uptodate.
If a user searches for up-to-date replace it in the query with uptodate.
By that you can still find specific in user-specific but up-to-date as well (and not only date).
Bonus
If a user searches for -well-known huge ports MySQL treats that as not include *well*, could include *known* and *huge*. Of course you could solve that with an other extra query variant as well, but with the trick above you remove the hyphen so the search query looks simply like that:
SELECT id
FROM texts
WHERE MATCH(text) AGAINST('-wellknown huge ports' IN BOOLEAN MODE)
I am trying to follow: http://dev.mysql.com/doc/refman/4.1/en/fulltext-natural-language.html
in an attempt to improve search queries, both in speed and the ability to order by score.
However when using this SQL ("skitt" is used as a search term just so I can try match Skittles).
SELECT
id,name,description,price,image,
MATCH (name,description)
AGAINST ('skitt')
AS score
FROM
products
WHERE
MATCH (name,description)
AGAINST ('skitt')
it returns 0 results. I am trying to find out why, I think I might have set my index's up wrong I'm not sure, this is the first time I've strayed away from LIKE!
Here is my table structure and data:
Thank you!
By default certain words are excluded from the search. These are called stopwords. "a" is an example of a stopword. You could test your query by using a word that is not a stopword, or you can disable stopwords:
How can I write full search index query which will not consider any stopwords?
If you want to also match prefixes use the truncation operator in boolean mode:
*
The asterisk serves as the truncation (or wildcard) operator. Unlike the other operators, it should be appended to the word to be affected. Words match if they begin with the word preceding the * operator.