mysql match against query - php

I am using mysql match against query in my search query like this way
MATCH(film_name) AGAINST ('the vacation' IN BOOLEAN MODE).
But previously i use this one
film_name like '%the vacation%'
So my question is that i am getting the right result now by using match and against but the problem is that when i am using like there i can use the % sign before and after the search string so if the search string present with in the string then it was return the result so plz tell how to write my " MATCH(film_name) AGAINST ('the vacation' IN BOOLEAN MODE) " so that it also behaves `like '%'.
If the file name is 'rocketsingh'
then if i run film_name like '%rocket%' then it shows me the result
but if i run MATCH(film_name) AGAINST ('rocket' IN BOOLEAN MODE) then it will not show any result. Please suggest what to do.

MATCH command allows only prefixed wildcards but not postfixed wilcards. Since single words are indexed, a postfix wildcard is impossible to manage in the usual way index does. You can't retrieve *vacation instantly from index because left characters are the most important part of index.

The answer is: You can't. The MATCH AGAINST operator matches words, not strings. There is a difference between the two. Also note that your example will also match vacation, the, vacation the or the something something vacation and other. You should read here what searches you can do.
You should stick to your first option with LIKE if you don't want word searches.

Related

Search for special chars in mysql full text search

I am doing a search function in php, and I am allowing BOOLEAN search, but when I enter text containing chars like #, the query fails.
For example, when I search for #everyone, it throws an error.
I tried to solve this by adding doublequotes, but it doesn't work as expected, since for the search #everyone, it works but returns rows containing everyone and #everone.
I would like to know how we can search for words containing special chars in mysql full text search
Here's my query (simplified) :
SELECT * FROM messages WHERE MATCH(body) AGAINST ('#everyone' IN BOOLEAN MODE)
By default, MySQL does not treat '#' as a valid character for a word. If you want to treat '#' it, then review the documentation on the subject.
After you have made the changes, then you will need to re-build your index.

Searching for a term using SQL MATCH which includes spaces

This may be a newbie question, as I'm not an expert in SQL. However, couldn't find the answer using Google.
I have a table called record_fields which contains the majority of my system's content, which I want to search in. The content cell is defined as LONGTEXT as it can include extremely long input.
Originally, I used (simplifying the query a bit for clarity sake):
SELECT * FROM record_fields WHERE LOWER(content) LIKE LOWER('%{$keyword}%')
Execution time aside, this query has one major issue. If I search for the term "post" it will return all content which has words like "poster", "posting" and others. I wanted to add a FULLTEXT search.
Now the query looks like this (again, simplified):
SELECT * FROM record_fields WHERE MATCH (content) AGAINST ('{$keyword}')
However, this is still problematic. With MATCH, if my system's users search for the words "Bank of America", for example, all records that either have the word "Bank" and "America" will be returned.
TL;DR - my question is this:
how do I use MATCH to search for exact phrases with space in them?
Any help would be highly appreciated, thanks in advance!
%{keyword}% matches all text sub-strings that include your keyword anywhere in the string. MATCH usually takes all keywords in the match string as individual search terms, and matches against each. You can use boolean mode and use a + symbol before each required keyword. Take a look at the MySQL reference for this.
Edited the answer to reflect Idan's response in not getting the results from the suggested %keyword solution.
You can use Match Against With Boolean Mode and you can put your input string inside '"{$keyword}"'.
Check last example in below link
https://dev.mysql.com/doc/refman/5.5/en/fulltext-boolean.html
SELECT * FROM record_fields WHERE MATCH (content) AGAINST ('"{$keyword}"' IN BOOLEAN MODE )

MySql can't decide between LIKE and MATCH for text search

I am building an application in Laravel. And I can't decide to go with Match() or Like for text searching.
I only want to do a text search on one column, that is a Varchar(42).
I will also filter out the query by some Where() statements, so it will not do a text search on all rows.
I am using mysql 5.6+ so Match works with my innobd engine.
Does Match() do good in a table that has about 30k rows?
Laravel ORM doesnt support match so my query looks like this:
$q = Input::get('query');
Post::whereRaw("MATCH(title) AGAINST(? IN BOOLEAN MODE)", array($q))->get();
Do I need to sanitize the "$q" in order to be safe from SQL injections? Since I'm using whereRaw()
The two capabilities are quite different, so the choice should be easy. MATCH is focused on words within the text. So, if you want to search by one or more words, then MATCH should be faster. However, MATCH is focused on words, so searching on numbers, stop words, and short words requires extra effort.
LIKE generally cannot make use of an index. This slows down such queries because every row needs to be processed. Of course, if the rest of the filtering reduces this to 100 rows, then it is not a big deal.
Also, LIKE can use an index for "prefix" searches -- that is, searches at the beginning of the string. So, LIKE 'abc%' can use an index. `LIKE '%abc%' cannot.

how can i match two strings even if they are 1 character different?

I have a large database of sentences, and a problem where sentences like "i'm good" do not match to "im good" and vise versa or "is that mine?" not matching with "is that mine" and vise versa when i would want them to be detected as a match.
I had made complicated and messy functions trying to do this with wildcards and researching but its just a big mess. and im sure there must be a way to search with this 1 character lee way. If i can i would like to control which characters get this lee way, like in my examples the main problem causers are the question mark and the half quote. (? ').
im currently using a plane select query with php and mysql to do the matching queries.
i would love some help to figure this out so i can clean up the big mess of code that is currently doing the job inconsistently.
in case anyone wants to see the code query checking for matches is like this:
$checkqwry = "select * from `eng-jap` where (eng = '$eng' or english = '$oldeng' or english = '$oldeng2') and (jap = '$jap' or japanese = '$oldjap' or japanese = '$oldjap2');";
the purpose of the query is to just check if there is already a translation with the $eng and $jap already in the DB. the reason you see $oldeng $oldeng2 and $oldeng3 and so on is like i said, my messy foolish attempts to match even if there is or is not a question mark and so on. where some of the $oldeng variables have questions marks or halfquotes and so on and the others dont. there is more code above appending and remove question marks and stuff. yes its a big mess.
You want to use a String Metric algorithm as mentioned above, PHP has this function built in http://php.net/manual/en/function.levenshtein.php as well as http://www.php.net/manual/en/function.similar-text.php.
MySQL doesn't implement this (specific algorithm) natively but some people have went ahead and wrote stored procedures to accomplish the same: http://www.artfulsoftware.com/infotree/queries.php#552
In my opinion using a String Metric that can handle arbitrary changes is better then stripping out punctuation, and can also catch omissions, transpositions, etc...
Probably better to simply strip non-alphanumeric characters out before comparing the strings.
You can use the replace function in sql to replace "'" with "" and "?" with "".
You might want to look at natural language full text searches in MySQL. Add a FULLTEXT index to the eng column.
ALTER TABLE `eng-jap` ADD FULLTEXT INDEX `full` (`eng`) ;
Then, use match function:
select * from `eng-jap` where match(eng) against ('Im happy');
This will return both I'm happy and Im happy
If you select the relevance score like:
select id, match(eng) against ('Im happy') from `eng-jap` where match(eng) against ('Im happy');
you can use it to further process the matches in PHP and filter.
[EDIT]: Just verified that the relevance score for yesterday and yesterday? are the same too:
select *, match(eng) against ('yesterday') as mc from `eng-jap`
Result is:
6, yesterday?, 0.9058732390403748
7, yesterday, 0.9058732390403748
Note: For Fulltext index to be applied, your mysql engine has to be MyISAM. Also, the sentence has to contain more than 3 characters. The index doesn't seem to match a word like 'yes'.

How do I include plurals but exclude singulars? [duplicate]

I am building a site with a requirement to include plural words but exclude singlular words, as well as include longer phrases but exclude shorter phrases found within it.
For example:
a search for "Breads" should return results with 'breads' within it, but not 'bread' or 'read'.
a search for "Paperback book" should return results with 'paperback book' within it, but not 'paperback' or 'book'.
The query I have tried is:
SELECT * FROM table WHERE (field LIKE '%breads%') AND (field NOT LIKE '%bread%')
...which clearly returned no results, even though there are records with 'breads' and 'bread' in it.
I understand why this query is failing (I'm telling it to both include and exclude the same strings) but I cannot think of the correct logic to apply to the code to get it working.
Searching for %breads% would NEVER return bread or read, as the 's' is a required character for the match. So just eliminate the and clause:
SELECT ... WHERE (field LIKE '%breads%')
SELECT ... WHERE (field LIKE '%paperback book%');
You should consider using FULL TEXT SEARCH.
This will solve your Bread/read issue.
I believe use of wildcards here isn't useful. Lets say you are using '%read%', now this would also return bread, breads etc, which is why I recommended Full Text Search
With MySQL you can use REGEXP instead of like which would give you better control over your query...
SELECT * FROM table WHERE field REGEXP '\s+read\s+'
That would at least enforce word boundaries around your query and gives you much better control over your matching - with the downside of a performance hit though.

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