[wp-trac] [WordPress Trac] #39140: Taxonomies - operator AND doesn't work properly for taxonomy hierarchies

[WordPress Trac]

#39140: Taxonomies - operator AND doesn't work properly for taxonomy hierarchies
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 Reporter:  bredefladen   |      Owner:
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Query         |    Version:  4.6.1
 Severity:  normal        |   Keywords:
  Focuses:                |
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 Hi,

 This is a problem discovered using WooCommerce shortcodes but has its core
 problem in the WP core according to my findings. I've already implemented
 a fix for this in a customer project.

 I’ve ran into problems using one of the Woo shortcodes and operator ‘AND’.
 This is questioned by others several times before (see links below) but it
 seems like the core of the problem is not solved. I’ve worked with the
 issue on WP 4.6.1 installation and come to what I believe is a solution
 (changes in file class-wp-tax-query.php).

 Even if the issue is found using Woo product categories I believe this is
 an issue for taxonomies in general.

 Problem:
 Using shortcode to retrieve a filtered product list and filtering on two
 or more product categories using operator “AND” fails when using one or
 more non-leaf (i.e. parent) product categories. There even seemed to be
 additional problems when using more than two leaf keywords. In general the
 "AND" didn't behave as expected.

 Other reports on the issue:
 [https://wordpress.org/support/topic/operator-and-on-product_category/]
 [https://wordpress.org/support/topic/woocommerce-display-products-from-
 two-categories-combined/]
 [https://wordpress.org/support/topic/woocommerce-product_category-and-
 operator-returns-no-results/]


 Examples using Woo shortcodes:

 Taxonomies (product categories) for Product1: '''Leaf'''CatA,
 '''Leaf'''CatB

 [product_category category=”'''Parent'''CatA, '''Leaf'''CatB”
 operator=”AND”] => '''Fails''' - shows nothing. Should show Product1

 [product_category category=”'''Leaf'''CatA, '''Leaf'''CatB”
 operator=”AND”] => '''Ok''' - shows Product1


 Reason:
 There is no individual and complete hierarchial evaluation of each
 taxonomy/category keyword specified in the shortcode.

 Solution that worked for me:
 The issue is found in the WP-core file class-wp-tax-query.php. I’ve
 modified three functions to correct the issue. This includes changes to
 the SQL-statements generated.

 Changes to file class-wp-tax-query.php:
 class WP_Tax_Query
 - function get_sql_for_clause – code
 - function clean_query – input params and code
 - function transform_query – input params and code

 You find my modified and running code/functions with my comments here
 (tagged with // BF):
 [https://gist.github.com/Nettsidespesialisten/5d4596e18dced3c7d97501f195ffe02e]

 This is my first ticket here so please notify me how to contribute the
 best way with this issue (providing code into SVN or other).


 Kind regards

 Brede

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Ticket URL: <https://core.trac.wordpress.org/ticket/39140>
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