Changeset 41377 for trunk/src/wp-includes/class-wp-term-query.php

Timestamp:

09/13/2017 02:47:07 PM (7 years ago)

Author:

boonebgorges

Message:

Taxonomy: Force a DISTINCT term query when result count matters.

Generally, duplicate terms returned by a term query are eliminated in PHP,
after the database query takes place. This technique doesn't work properly
when the query parameters specify the number of results, since the results
of a SELECT ... LIMIT x... query may be deduplicated to a count less than
x. In these cases, we force the original query to be DISTINCT.

Props elvishp2006.
Fixes #41796.

File:

• trunk/src/wp-includes/class-wp-term-query.php (modified) (3 diffs)

trunk/src/wp-includes/class-wp-term-query.php

@@ -552 +552 @@
         }
 
+        $do_distinct = false;
+
+        /*
+         * Duplicate terms are generally removed when necessary after the database query.
+         * But when a LIMIT clause is included in the query, we let MySQL enforce
+         * distinctness so the count is correct.
+         */
+        if ( ! empty( $limits ) && 'all_with_object_id' !== $args['fields'] ) {
+            $do_distinct = true;
+        }
 
         if ( ! empty( $args['search'] ) ) {
@@ -569 +579 @@
             $join .= $mq_sql['join'];
             $this->sql_clauses['where']['meta_query'] = preg_replace( '/^\s*AND\s*/', '', $mq_sql['where'] );
-            $distinct .= "DISTINCT";
-
+            $do_distinct = true;
         }
 
@@ -632 +641 @@
         $where = implode( ' AND ', $this->sql_clauses['where'] );
 
+        $distinct = $do_distinct ? 'DISTINCT' : '';
+
         /**
          * Filters the terms query SQL clauses.