By Using Full Text Search not searching the exact value for multiple words.
This is the Query
SELECT * FROM csv WHERE match(data) against('"TMN PANTAI"' IN BOOLEAN MODE)
Its showing the result but its searching with "TMN" and "PANTAI" and "TMN PANTAI"
How can i search the exact match using "TMN PANTAI"?
FULL-TEXT doesn't take space into consideration, that is why you cannot use it.
If you still want to take advantage of full-text index, you can shorten up the resultset by filtering using match against query and add an additional LIKE condition. This will be efficient than querying with LIKE on the whole table, since the LIKE will now have lesser records to filter.
SELECT * FROM csv WHERE match(data) against('+TMN +PANTAI' IN BOOLEAN MODE)
AND data like '%TMN PANTAI%'
Related
I have a table data with about 500.000 records, the table have:
id,
title,
created_date,
content...
columns. In those column, the content column contain large size text.
I've used search query:
SELECT count(*) from data WHERE content LIKE (%keyword%);
This query have execute time around 9 seconds.
I tried to use Full Text Search and using this query
SELECT count(*) from data
WHERE MATCH(content) AGAINST ('keyword*' IN BOOLEAN MODE);
The query have much shorter execute time, just about 0.4 second but the results is not the same as query which use LIKE operator.
As the MySQL documentation, the full text search query above can only return records that have type like "keyword---" and ignore "---keyword" and it can not meet my search requirement.
So, i want to ask if we have any other way to replace LIKE operator or any way to speed up the searching with LIKE ?
You can use LOCATE():
SELECT COUNT(*) FROM data WHERE LOCATE("keyword", content) > 0
Or INSTR():
SELECT COUNT(*) FROM data WHERE INSTR(content, "keyword") > 0
In case you have a lot of text in your DB and need such kind of search you could do several things:
you can configure full-text search indexes in MySQL
you can use another full-text search DB engines like Sphinx or Elastic Search. They are much more powerful and scalable comparing to native MySQL full-text search.
Also about full-text search in MySQL. Try to use + instead of *.
With * words match if they begin with the word preceding the * operator.
A leading + sign indicates that a word must be present in each row that is returned.
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 have strings like the following in my VARCHAR InnoDB table column:
"This is a {{aaaa->bbb->cccc}} and that is a {{dddd}}!"
Now, I'd like to search for e.g. {{xxx->yyy->zzz}}. Brackets are part of the string. Sometimes searched together with another colum, but which only contains an ordinary id and hence don't need to be considered (I guess).
I know I can use LIKE or REGEXP. But these (already tried) ways are too slow. Can I introduce a fulltext index? Or should I add another helping table? Should I replace the special characters {, }, -, > to get words for the fulltext search? Or what else could I do?
The search works with some ten-thousand rows and I assume that I often get about one hundred hits.
This link should give you all the info you need regarding FULLTEXT indexes in MySQL.
MySQL dev site
The section that you will want to pay particular attention to is:
"Full-text searching is performed using MATCH() ... AGAINST syntax. MATCH() takes a comma-separated list that names the columns to be searched. AGAINST takes a string to search for, and an optional modifier that indicates what type of search to perform. The search string must be a string value that is constant during query evaluation. This rules out, for example, a table column because that can differ for each row."
So in short, to answer your question you should see an improvement in query execution times by implementing a full text index on wide VARCHAR columns. Providing you are using a compatible storage engine ( InnoDB or MyISAM)
Also here is an example of how you can query the full text index and also an additional ID field as hinted in your question:
SELECT *
FROM table
WHERE MATCH (fieldlist) AGAINST ('search text here')
AND ( field2= '1234');
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
If I store an HTML TEXTAREA in my ODBC database each time the user submits a form, what's the SELECT statement to retrieve 1) all rows which contain a given sub-string 2) all rows which don't (and is the search case sensitive?)
Edit: if LIKE "%SUBSTRING%" is going to be slow, would it be better to get everything & sort it out in PHP?
Well, you can always try WHERE textcolumn LIKE "%SUBSTRING%" - but this is guaranteed to be pretty slow, as your query can't do an index match because you are looking for characters on the left side.
It depends on the field type - a textarea usually won't be saved as VARCHAR, but rather as (a kind of) TEXT field, so you can use the MATCH AGAINST operator.
To get the columns that don't match, simply put a NOT in front of the like: WHERE textcolumn NOT LIKE "%SUBSTRING%".
Whether the search is case-sensitive or not depends on how you stock the data, especially what COLLATION you use. By default, the search will be case-insensitive.
Updated answer to reflect question update:
I say that doing a WHERE field LIKE "%value%" is slower than WHERE field LIKE "value%" if the column field has an index, but this is still considerably faster than getting all values and having your application filter. Both scenario's:
1/ If you do SELECT field FROM table WHERE field LIKE "%value%", MySQL will scan the entire table, and only send the fields containing "value".
2/ If you do SELECT field FROM table and then have your application (in your case PHP) filter only the rows with "value" in it, MySQL will also scan the entire table, but send all the fields to PHP, which then has to do additional work. This is much slower than case #1.
Solution: Please do use the WHERE clause, and use EXPLAIN to see the performance.
Info on MySQL's full text search. This is restricted to MyISAM tables, so may not be suitable if you wantto use a different table type.
http://dev.mysql.com/doc/refman/5.0/en/fulltext-search.html
Even if WHERE textcolumn LIKE "%SUBSTRING%" is going to be slow, I think it is probably better to let the Database handle it rather than have PHP handle it. If it is possible to restrict searches by some other criteria (date range, user, etc) then you may find the substring search is OK (ish).
If you are searching for whole words, you could pull out all the individual words into a separate table and use that to restrict the substring search. (So when searching for "my search string" you look for the the longest word "search" only do the substring search on records containing the word "search")
I simply use SELECT ColumnName1, ColumnName2,.....WHERE LOCATE(subtr, ColumnNameX)<>0
To get rows with ColumnNameX having the substring.
Replace <> with = to get rows NOT having the substring.