I would like to query a single column (varchar):
sample datarows:
1) The fox jumps like a foo on my bar
2) Jumpers are not cool
3) Apple introduced iJump
When I enter a search criteria like... jump
I expect to get a resultset of: jumps, Jumpers, iJump
(So I dont want the complete row)
Currently I'm using MySQL (I'm open to suggestions as long it's open source)
Since you're using MySQL, I might suggest looking into LIB_MYSQLUDF_PREG.
This open source library will provide you with additional regex functionality, including the PREG_CAPTURE function, which extracts a regex match from a string.
Using this function, you could easily build a regex to return the match you're looking for... Something like:
\b\w*jump\w*\b
Getting any row with your search criteria is easy:
SELECT sentence
FROM sentences
WHERE sentence LIKE '%jump%'
I'd probably do the rest in application logic, since doing it in the database doesn't help you at all.
Also, any method of splitting a string and handling it will probably be database-specific, so you would need to say which one you're using.
Related
I have a table dictionary which contains a list of words Like:
ID|word
---------
1|hello
2|google
3|similar
...
so i want if somebody writes a text like
"helo iam looking for simlar engines for gogle".
Now I want to check every word if it exists in the database, if not it should
get me the similar word for the word. For example: helo = hello, simlar = similar, gogle = google.
Well, i want to fix the spelling errors. In my database i have a full dictionary of all english words. I coudn't find any mysql function which helps me. LIKE isn't helpfull in my situation.
you can use soundex() function for comparing phonetically
your query should be something like:
select * from table where soundex(word) like soundex('helo');
and this will return you the hello row
There is a function that does roughly want you want, but it's intensive and will slow queries down. You might be able to use in your circumstances, I have used it before. It's called Levenshtein. You can get it here How to add levenshtein function in mysql?
What you want to do is called a fuzzy search. You could use the SOUNDEX function in MySQL, documented here:
http://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_soundex
You query would look like:
SELECT * FROM dictionary where SOUNDEX(word) = SOUNDEX(:yourSearchTerm)
... where your search term is bound to the :yourSearchTerm parameter value.
A next step would be to try implementing and making use of a Levenshtein function in MySQL. One is described here:
http://www.artfulsoftware.com/infotree/qrytip.php?id=552
The Levenshtein distance between two strings is the minimum number of
operations needed to transform one string into the other, where an
operation may be insertion, deletion or substitution of one character.
You might also consider looking into databases that are aimed at full text searching, such as Elastic Search, which provides this natively:
https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-fuzzy-query.html
I am trying to put Solr search results that contain my search phrase in a specific field (here resourcename) on the top of the result set.
I am a beginner on Solr. I have searched the web for quite a while and found some related questions, like:
Use function query for boosting score in Solr
SolrNet queries with boost functions
Then I started experimenting myself with queries like these:
https://localhost:8898/solr/collection1/select?defType=edismax&fl=resourcename&indent=on&q=resourcename:"test"*^200,%20content:"test"*^1&qf=resourcename^200%20content^2&rows=1000&wt=json
https://localhost:8898/solr/collection1/select?bf=if(exists(resourcename),100,1)&defType=edismax&fl=resourcename&indent=on&q=resourcename:"test"*^200,%20content:"test"*^1&rows=1000&wt=json
https://localhost:8898/solr/collection1/select?bf=if(exists(resourcename),100,1)&defType=edismax&fl=resourcename&indent=on&q=*:"test"*&rows=1000&wt=json
https://localhost:8898/solr/collection1/select?defType=edismax&fl=resourcename&indent=on&q=*:"test"*&qf=resourcename^200%20content^2&rows=1000&wt=json
But, no matter what I try, I get results containing the word test in the resourcename all over the place and not only on the top of the results.
Any ideas what I might be missing or doing wrong?
There are a lot of syntax mistakes, I would recommend to take a look to the solr wiki for query parsers[1] .
As a suggestion, always take a look to the parsed query and explore the debug functionality for search results.
To get the behavior you are asking I would use the following request parameters (quoting from the wiki):
q=foo bar
qf=field1^5 field2^10
pf=field1^50 field2^20
defType=dismax
With these parameters, the Dismax Query Parser generates a query that looks something like this:
(+(field1:foo^5 OR field2:foo^10) AND (field1:bar^5 OR field2:bar^10))
But it also generates another query that will only be used for boosting results:
field1:"foo bar"^50 OR field2:"foo bar"^20
In this way you can boost results according to the matches in some fields, with related boosts and then also boost phrases appearing in specific other fields.
[1] https://cwiki.apache.org/confluence/display/solr/The+Extended+DisMax+Query+Parser
I have a table dictionary which contains a list of words Like:
ID|word
---------
1|hello
2|google
3|similar
...
so i want if somebody writes a text like
"helo iam looking for simlar engines for gogle".
Now I want to check every word if it exists in the database, if not it should
get me the similar word for the word. For example: helo = hello, simlar = similar, gogle = google.
Well, i want to fix the spelling errors. In my database i have a full dictionary of all english words. I coudn't find any mysql function which helps me. LIKE isn't helpfull in my situation.
you can use soundex() function for comparing phonetically
your query should be something like:
select * from table where soundex(word) like soundex('helo');
and this will return you the hello row
There is a function that does roughly want you want, but it's intensive and will slow queries down. You might be able to use in your circumstances, I have used it before. It's called Levenshtein. You can get it here How to add levenshtein function in mysql?
What you want to do is called a fuzzy search. You could use the SOUNDEX function in MySQL, documented here:
http://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_soundex
You query would look like:
SELECT * FROM dictionary where SOUNDEX(word) = SOUNDEX(:yourSearchTerm)
... where your search term is bound to the :yourSearchTerm parameter value.
A next step would be to try implementing and making use of a Levenshtein function in MySQL. One is described here:
http://www.artfulsoftware.com/infotree/qrytip.php?id=552
The Levenshtein distance between two strings is the minimum number of
operations needed to transform one string into the other, where an
operation may be insertion, deletion or substitution of one character.
You might also consider looking into databases that are aimed at full text searching, such as Elastic Search, which provides this natively:
https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-fuzzy-query.html
In field post_content I have a string like this in nearly 800 rows:
http://somesite.com/">This is some site</a>
I need to remove everything from "> onwards so that it leaves just the URL. I can't do a straight find and replace because the text is unique.
Any clues? This is really my first foray into MySQL database modifications but I did do an extensive search before posting here.
Thanks,
~Kyle~
From this site: http://www.regular-expressions.info/mysql.html
LIB_MYSQLUDF_PREG
If you want more regular expression power in your database, you can consider using LIB_MYSQLUDF_PREG. This is an open source library of MySQL user functions that imports the PCRE library. LIB_MYSQLUDF_PREG is delivered in source code form only. To use it, you'll need to be able to compile it and install it into your MySQL server. Installing this library does not change MySQL's built-in regex support in any way. It merely makes the following additional functions available:
Here it comes...
PREG_CAPTURE extracts a regex match from a string. PREG_POSITION returns the position at which a regular expression matches a string. PREG_REPLACE performs a search-and-replace on a string. PREG_RLIKE tests whether a regex matches a string.
Sounds exactly what you're looking for.
All these functions take a regular expression as their first parameter. This regular expression must be formatted like a Perl regular expression operator. E.g. to test if regex matches the subject case insensitively, you'd use the MySQL code PREG_RLIKE('/regex/i', subject). This is similar to PHP's preg functions, which also require the extra // delimiters for regular expressions inside the PHP string.
See this post: How to do a regular expression replace in MySQL?
Either that or you could just write a script in any lanugage which goes through each record, does a regex replacement and then updates the field. For more info on regex, see here: http://www.regular-expressions.info/reference.html
There's a number of options. One might be to use SUBSTRING_INDEX():
UPDATE
table
SET field = SUBSTRING_INDEX( field, '">', 1 )
It's possible - there is a syntax for User Defined Functions which would let you pass in a regular expression pattern that matches the link and strips everything else.
However, this is quite complicated for somebody new to MySQL, and from your question, this sounds like a one-off. In which case - why not just use Excel and then reimport the data?
Great stuff!
All seems doable with a little bit of time and self education.
In the end, I exported that table as a CSV in Sequel Pro and did some nifty find and replace work in Coda. Not as sophisticated as your suggestions, but it worked.
Thanks again,
~Kyle~
I want search companies from my company table when i give company name...here am using like operator
eg: saravana stores
it gives the result saravana stores texttiles,saravana stores thanga maligai,etc(which is contained with saravana stroes...coz of using LIKE operator)
Now my problem is when i give lcd projectors in the companyname, also want to fetch the records which are contained with the only projector word...but like operator gave the results with the 'lcd projector'
am making clear?
Try:
WHERE (name LIKE '%saravana%' OR name LIKE '%stores%')
This has two disadvantages:
It can't use an index so it will be slow.
It can give you matches you don't want like 'bestorest' matches '%stores%'.
You might want to use a full text search instead. You could also consider an external engine such as Lucene.
If you want proper fultext search, I highly recommend trying Lucene or Sphinx.
I know it would get a little complicated, but it's worth it for the end result.
Mark Byers is right.
To get more efficiency
After query dividing to words you can modify search input to get word base and unify searching to get smth lika:
WHERE (name LIKE '%sarava%' OR name LIKE '%stor%')