• 0

[mysql] fulltext across multiple tables


Question

I am writing a search tool to search our product inventory. The relevant parts of the database structure are:

TABLE products

--product_ID (integer)

--product_name (varchar50)

--product_shortDescription (varchar255)

--product_MRNumber (varchar50)

TABLE productDescriptions

--description_ID (integer)

--product_ID (integer)

--description_text (text)

TABLE productReviews

--review_ID (integer)

--product_ID (integer)

--review_text (text)

The JOINs are kinda obvious, but the products table JOINS against both productDescriptions and productReviews on the product_ID field. Currently this is a one-to-one relationship (reviews will become one to many later, will add a user_ID field and have many reviews by many users against a single product - but that is not for now).

The fields I want to search on are:

products.product_name

products.product_shortDescription

products.product_MRNumber

productDescriptionsdescription_text

productReviewsreview_text

I have performed the following to create the FULLTEXT indices, all of which returned no errors:

ALTER TABLE products ADD FULLTEXT(product_name, product_shortDescription, product_MRNumber); 
ALTER TABLE productDescriptions ADD FULLTEXT(description_text); 
ALTER TABLE productReviews ADD FULLTEXT(review_text);

However, things are NOT going well...

Firstly, if I perform the following, I get an error "Can't find FULLTEXT index matching the column list":

SELECT
	*
FROM
	_products
WHERE
	MATCH(
   		product_shortDescription
   	) AGAINST ('watt')

My GUESS is that this is down to the product_shortDescription field not being TEXT but rather VARCHAR - so no FULLTEXT can actually be applied? If so, suggestions appreciated. This shortDescription is just a very short one line description used more as a quick identifier than a full-on description.

Secondly, I am finding that certain searches are producing no results when they should be returning at least one item. For example, the following returns an empty set:

SELECT
	*
FROM
	productReviews
WHERE
	MATCH(
		review_description
	) AGAINST ('deck')

whereas this returns 7 rows:

SELECT
	*
FROM
	_tbl_inventory_product_reviews
WHERE
		review_description LIKE ('%deck%')

What am I doing wrong? I would appreciate any help - sorry if I come across "noob" - I have used FULLTEXT before in MS SQL, but not within MySql...

9 answers to this question

Recommended Posts

  • 0

At a guess, what you have is a fulltext index of the three columns of the product db combined, not the individual columns. Do this, and then try your search query again:

ALTER TABLE products ADD FULLTEXT(product_name), FULLTEXT(product_shortDescription), FULLTEXT(product_MRNumber);

  • 0

DaveLegg: Perfect, that 100% solved the first issue. I didn't realise it made a FULLTEXT index of the combined fields - I used the ALTER command wrongly without reading up on it.

So now, the second issue...

I am finding that certain searches are producing no results when they should be returning at least one item. For example, the following returns an empty set:

SELECT
	*
FROM
	productReviews
WHERE
	MATCH(
		review_description
	) AGAINST ('deck')

whereas this returns 7 rows:

SELECT
	*
FROM
	_tbl_inventory_product_reviews
WHERE
		review_description LIKE ('%deck%')

  • 0

My bad, yes, they are the same tables, I simply retyped them for a more logical name in this thread.

To clarify:

This returns 0 results:

SELECT * FROM productReviews WHERE MATCH(review_description) AGAINST ('deck')

This returns 7 results

SELECT * FROM productReviews WHERE review_description LIKE ('%deck%')

Weirdly:

This returns 4 results:

SELECT * FROM _tbl_inventory_product_reviews WHERE MATCH(review_description) AGAINST ('portable')

This returns 4 results:

SELECT * FROM _tbl_inventory_product_reviews WHERE review_description LIKE ('%portable%')

  • 0

This may be of relevance:

  Quote
A few restrictions affect MySQL FULLTEXT indices. Some of the default behaviors of these restrictions can be changed in your my.cnf or using the SET command.

* FULLTEXT indices are NOT supported in InnoDB tables.

* MySQL requires that you have at least three rows of data in your result set before it will return any results.

* By default, if a search term appears in more than 50% of the rows then MySQL will not return any results.

* By default, your search query must be at least four characters long and may not exceed 254 characters.

* MySQL has a default stopwords file that has a list of common words (i.e., the, that, has) which are not returned in your search. In other words, searching for the will return zero rows.

* According to MySQL's manual, the argument to AGAINST() must be a constant string. In other words, you cannot search for values returned within the query.

Source

  • 0

Im just curious. With your first example searching against "deck" what happens if you try to search "in boolean mode"

SELECT * FROM productReviews WHERE MATCH(review_description) AGAINST ('deck', IN BOOLEAN MODE);

I had an issue similar to this in the past.

This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Posts

    • Ah .. lockout for suspicious activity. I bet they uploaded the SanDisk utility detected as malware
    • Microsoft 365 will soon disable outdated authentication protocols for file access by Usama Jawad On a fairly regular basis, Microsoft disables outdated protocols that are used to access its services. In the past few years, the company has deprecated Basic Auth in Exchange Online and cut access to Outlook for third-party apps relying on this protocol. Now, it has decided to get rid of old authentication protocols for file access across Microsoft 365 services. As reported by Bleeping Computer, Microsoft has posted a message on its Microsoft 365 Admin Center. Starting from mid-July 2025, the company will begin disabling legacy authentication protocols used to access files across Microsoft 365 and Office apps, SharePoint, and OneDrive. Essentially, applications or services which use the Relying Party Suite (RPS) or FrontPage Remote Procedure Call (FPRPC) will to perform browser-based authentication to perform open operations on Office files will no longer be able to do so. As expected, this is primarily being done to improve the cybersecurity posture of various services. Microsoft states that RPS can be brute-forced and phished with relative ease as it is fairly outdated. Similarly, FPRPC is typically used for remote web page authoring and it is susceptible to exploitation through various vulnerabilities too. As such, both of these protocols will be disabled by default starting from mid-July 2025, with the rollout of this change targeting completion by August 2025. The Redmond tech giant will update the protocol baseline by default without mandating any licensing changes for customers. In addition, once these modifications are rolled out, Microsoft 365 will require admin consent to get third-party access to files and sites. IT admins can view the guidance available here to configure admin consent workflows. Microsoft says that these changes align with the principles of its Secure Future Initiative (SFI). Earlier today, it announced the rollout of improved security defaults for Windows 365 citing the same reasons too.
    • This is how you kill your own business.
    • It does and it can... I took an i3 board and upgraded it to my FX8350... no issues, just put in new drivers over the top that Windows didn't. Not the issue for me, (though I eventually did do a new install from 23H2 to 24H2)... I was on 22H2 at the time. The issue is activation. You may get hit with having to activate again.
  • Recent Achievements

    • First Post
      Fuzz_c earned a badge
      First Post
    • First Post
      TIGOSS earned a badge
      First Post
    • Week One Done
      slackerzz earned a badge
      Week One Done
    • Week One Done
      vivetool earned a badge
      Week One Done
    • Reacting Well
      pnajbar earned a badge
      Reacting Well
  • Popular Contributors

    1. 1
      +primortal
      705
    2. 2
      ATLien_0
      283
    3. 3
      Michael Scrip
      217
    4. 4
      +FloatingFatMan
      195
    5. 5
      Steven P.
      130
  • Tell a friend

    Love Neowin? Tell a friend!