Merge "RCFilters: Display specific error if query times out"

[lhc/web/wiklou.git] / includes / libs / rdbms / database / IDatabase.php

diff --git a/includes/libs/rdbms/database/IDatabase.php b/includes/libs/rdbms/database/IDatabase.php
index 67e8e85..868c2d4 100644 (file)
--- a/includes/libs/rdbms/database/IDatabase.php
+++ b/includes/libs/rdbms/database/IDatabase.php
@@ -620,6 +620,19 @@ interface IDatabase {
         * This includes the user table in the query, with the alias "a" available
         * for use in field names (e.g. a.user_name).
         *
+        * Joins using parentheses for grouping (since MediaWiki 1.31) may be
+        * constructed using nested arrays. For example,
+        *
+        *    [ 'tableA', 'nestedB' => [ 'tableB', 'b2' => 'tableB2' ] ]
+        *
+        * along with `$join_conds` like
+        *
+        *    [ 'b2' => [ 'JOIN', 'b_id = b2_id' ], 'nestedB' => [ 'LEFT JOIN', 'b_a = a_id' ] ]
+        *
+        * will produce SQL something like
+        *
+        *    FROM tableA LEFT JOIN (tableB JOIN tableB2 AS b2 ON (b_id = b2_id)) ON (b_a = a_id)
+        *
         * All of the table names given here are automatically run through
         * Database::tableName(), which causes the table prefix (if any) to be
         * added, and various other table name mappings to be performed.