I have a table that is populated with certain values e.g.
| CODE | NAME | NB: THIS IS A VERY BASIC EXAMPLE
| zygnc | oscar alpha |
| ab-cd | delta tiger |
| fsdys | delta bravo |
Using MySQL Full-Text Boolean search i would like to search this table for all names containing 'delta' but exclude the first result basic on its unique code 'ab-cd'. This code contains a minus sign and this is a requirement and removing this would not be possible.
So the following query 'should' in my mind accommodate for this:
SELECT code, name
FROM items
WHERE MATCH (code, name)
AGAINST ('delta -"ab-cd"' IN BOOLEAN MODE)
However, running this query does not product the desired result in that the result does still contain the row with the code that is meant to be excluded, 'ab-cd'.
The Coalition of these two tables are set to utf8_bin.
The ft_min_word_len value is set to 4.
Could someone possibly suggest a reason for this behavior, I assume that it treats the string possibly as two separate values, e.g. "-ab", "-cd" and as the ft_min_word_len value is 4, neither of these two strings can produce any result?
I would think that the use of the encapsulation "", would mean that the second minus sign would be treated as literal but it seems that this is not the case. Perhaps it has something to do with the table coalition that i am not aware of?
In any case, any suggestions/advice/input/feedback/direction would be greatly appreciated, thank you!!
You need to change the value of variable ft_min_word_len in my.cnf file.
By default ft_min_word_len value is 3. Once change the variable, you need to restart the server.
Here "ab-cd" treated as two words as "ab" and "cd". So minimum word length is not matched with the words.
Related
So I have a slug column in my table and due to some bad coding, some of my slugs are messed up and need to be fixed.
I need to find all slugs that have a hyphen on both sides of exactly 5 digits, somewhere in the middle of the string.
So here's three samples of slugs:
321-sw-2nd-ave-portland-or-97204-2-3-4-5
321-sw-2nd-ave-portland-or-97204-2-3
430-e-25th-st-tacoma-wa-98421
My expression would match the first and second but not the third one.
I would like to then get rid of those extra things after the zip code.
Here's what I have tried so far, but my Regex skills are lacking big time.
^(.)*d{5}-(.)*$
You are attempting to match on the entire string. I would simply do a partial match on the part that you are interested in. Another problem with your regex is that you use d to represent a digit: MySQL wants \\d; also, this notation is only supported from 8.0 (in earlier versions, you need [0-9]).
Consider:
slug RLIKE '[0-9]{5}-'
Demo on DB Fiddle:
with t as (
select '321-sw-2nd-ave-portland-or-97204-2-3-4-5' slug
union all select '321-sw-2nd-ave-portland-or-97204-2-3'
union all select '430-e-25th-st-tacoma-wa-98421'
)
select slug from t where slug RLIKE '[0-9]{5}-'
| slug |
| :--------------------------------------- |
| 321-sw-2nd-ave-portland-or-97204-2-3-4-5 |
| 321-sw-2nd-ave-portland-or-97204-2-3 |
I have a table, let's call it A, with a FULLTEXT index on its name field.
This table, containing around 1200 rows, contains a single row whose name field has a value of "TELEVISORI"
This query:
SELECT A.name, MATCH(name) AGAINST ('Televisori') AS `match`
FROM A
Results in (not the exact value, but I remember it being around 8):
+------------+-----------+
| name | match |
+------------+-----------+
| TELEVISORI | 8.3947893 |
+------------+-----------+
Whereas this one:
SELECT A.name, MATCH(name) AGAINST ('Televisore') AS `match`
FROM A
yields no results.
Things I've checked:
The word is not a stop word
Its length is over 4 characters (rather, 3 since I'm using InnoDB?)
The word appears in less than 50% of records - It's the only one in hundreds.
I tried changing the casing of the words in every possible combination just to be completely sure, but that shouldn't be it since I'm using a case insensitive collation. Also, it matches without a problem when I use "Televisori"
Is there anything I'm missing?
I'm trying to query using mysql FULLTEXT, but unfortunately its returning empty results even the table contain those input keyword.
Table: user_skills:
+----+----------------------------------------------+
| id | skills |
+----+----------------------------------------------+
| 1 | Dance Performer,DJ,Entertainer,Event Planner |
| 2 | Animation,Camera Operator,Film Direction |
| 3 | DJ |
| 4 | Draftsman |
| 5 | Makeup Artist |
| 6 | DJ,Music Producer |
+----+----------------------------------------------+
Indexes:
Query:
SELECT id,skills
FROM user_skills
WHERE ( MATCH (skills) AGAINST ('+dj' IN BOOLEAN MODE))
Here once I run the above query none of the DJ rows are returning. In the table there are 3 rows with is having the value dj.
A full text index is the wrong approach for what you are trying to do. But, your specific issue is the minimum word length, which is either 3 or 4 (by default), depending on the ending. This is explained in the documentation, specifically here.
Once you reset the value, you will need to recreate the index.
I suspect you are trying to be clever. You have probably heard the advice "don't store lists of things in delimited strings". But you instead countered "ah, but I can use a full text index". You can, although you will find that more complex queries do not optimize very well.
Just do it right. Create the association table user_skills with one row per user and per skill that the user has. You will find it easier to use in queries, to prevent duplicates, to optimize queries, and so on.
Your search term is to short
as in mysql doc
Some words are ignored in full-text searches:
Any word that is too short is ignored. The default minimum length of words that are found by full-text searches is three characters for
InnoDB search indexes, or four characters for MyISAM. You can control
the cutoff by setting a configuration option before creating the
index: innodb_ft_min_token_size configuration option for InnoDB search
indexes, or ft_min_word_len for MyISAM.
.
Boolean full-text searches have these characteristics:
They do not use the 50% threshold.
They do not automatically sort rows in order of decreasing relevance.
You can see this from the preceding query result: The row with the
highest relevance is the one that contains “MySQL” twice, but it is
listed last, not first.
They can work even without a FULLTEXT index, although a search
executed in this fashion would be quite slow.
The minimum and maximum word length full-text parameters apply.
https://dev.mysql.com/doc/refman/5.6/en/fulltext-natural-language.html
https://dev.mysql.com/doc/refman/5.6/en/fulltext-boolean.html
I need to store some flags for user records in a MySQL table (I'm using InnoDB):
---------------------------
| UserId | Mask |
| -------------------------
| 1 | 00000...001 |
| 2 | 00000...010 |
---------------------------
The number of flags is bigger than 64, so I can't use a BIGINT or BIT type to store the value.
I don't want to use many-to-many association tables, because each user can have more than one profile, each one with its set of flags and it would grow too big very quickly.
So, my question is, is it possible to store these flags in a VARCHAR, BLOB or TEXT type column and still do bitwise operations on them? If yes, how?
For now I just need one operation: given a mask A with X bits set to 1 what users have at least those X bits set to 1.
Thanks!
EDIT
To anyone reading this, I've found a solution (for me, at least). I'm using a VARCHAR for the mask field and when searching for a specific mask I use this query:
select * from my_table where mask like '__1__1'
Every record that has the 3rd and last bit set to on will be returned. The "_" symbol is a SQL placehoder for "any single character" (mySQL only, perhaps?).
In terms of speed is doing fine right now, will have to check later when my user base grows.
Anyway, thanks for your input. Other ideas welcomed, of course.
I am facing a problem regarding a string comparison in MySQL.
I have the following table,
res_id | image_min_allowed_dimension | canvas_dimension
1 400x500 8x10
2 800x600 11x14
As you can see in this table,
image_min_allowed_dimension column has 2 sets of record. Ans also canvas_dimension has 2 sets
Now, my goal is to get these 2 sets of record with a given value for image_min_allowed_dimension.
Say, if I give 1024x768 for image_min_allowed_dimension in the PHP script it will give me the 2 sets of record from canvas_dimension field.
The probable algo would be,
Fetch All Records as canvas_dimension
IF image_min_allowed_dimension is Less than or equal to a given value(i.e, 1024x768)
ELSE IF the given value is greater than image_min_allowed_dimension then return nothing.
But as the fields are varchar, how can I achieve that.?
Please help.
Refactor your schema to store your resolutions in a sane manner.
res_id | image_min_allowed_width | image_min_allowed_height | canvas_width | canvas_height
Your future self will thank you for the extra effort.