Merge remote-tracking branch 'origin/5.next' into docs-string-agg

# Conflicts:
#	docs/en/appendices/5-4-migration-guide.md

Author: dereuromark

docs/en/appendices/5-4-migration-guide.md

@@ -44,6 +44,7 @@ version is reported as `unknown`), the header is omitted.
 - The default eager loading strategy for `HasMany` and `BelongsToMany` associations
   has changed from `select` to `subquery`. If you need the previous behavior,
   explicitly set `'strategy' => 'select'` when defining associations.
+  See [Associations](../orm/associations#has-many-associations) for more details.
 
 ### Controller
 
@@ -101,6 +102,10 @@ version is reported as `unknown`), the header is omitted.
 - Added `FunctionsBuilder::stringAgg()` for portable string aggregation.
   Translates to `STRING_AGG` or `GROUP_CONCAT` per driver.
   See [Query Builder](../orm/query-builder#string-aggregation).
+- Added `except()` and `exceptAll()` methods on `SelectQuery` for `EXCEPT`
+  and `EXCEPT ALL` set operations. `EXCEPT ALL` is supported on PostgreSQL
+  and recent MySQL/MariaDB versions; it is not supported on SQLite or SQL Server.
+  See [Query Builder](../orm/query-builder#except).
 - Added PostgreSQL index access method reflection. Non-btree indexes (`gin`,
   `gist`, `spgist`, `brin`, `hash`) are now reflected with an `accessMethod`
   field and regenerated with the correct `USING` clause. The `Index` class

docs/en/orm/associations.md

@@ -462,9 +462,12 @@ Possible keys for hasMany association arrays include:
 - **propertyName**: The property name that should be filled with data from the
   associated table into the source table results. By default, this is the
   underscored & plural name of the association so `comments` in our example.
-- **strategy**: Defines the query strategy to use. Defaults to 'subquery'. The
-  other valid value is 'select', which uses the `IN` list of parent keys
+- **strategy**: Defines the query strategy to use. Defaults to `subquery`. The
+  other valid value is `select`, which uses the `IN` list of parent keys
   directly instead of a subquery.
+::: tip New default strategy in version 5.4+
+The default strategy has changed from `select` to `subquery` in order to improve performance when the number of parent keys is large.
+:::
 - **saveStrategy**: Either `append` or `replace`. Defaults to `append`. When `append` the current
   records are appended to any records in the database. When `replace` associated
   records not in the current set will be removed. If the foreign key is a nullable
@@ -616,9 +619,12 @@ Possible keys for belongsToMany association arrays include:
 - **propertyName**: The property name that should be filled with data from the
   associated table into the source table results. By default, this is the
   underscored & plural name of the association, so `tags` in our example.
-- **strategy**: Defines the query strategy to use. Defaults to 'subquery'. The
-  other valid value is 'select', which uses the `IN` list of parent keys
+- **strategy**: Defines the query strategy to use. Defaults to `subquery`. The
+  other valid value is `select`, which uses the `IN` list of parent keys
   directly instead of a subquery.
+::: tip New default strategy in version 5.4+
+The default strategy has changed from `select` to `subquery` in order to improve performance when the number of parent keys is large.
+:::
 - **saveStrategy**: Either `append` or `replace`. Defaults to `replace`.
   Indicates the mode to be used for saving associated entities. The former will
   only create new links between both side of the relation and the latter will

docs/en/orm/query-builder.md

@@ -2237,6 +2237,39 @@ $unpublished->intersectAll($inReview);
 `intersect()` and `intersectAll()` were added.
 :::
 
+### Except
+
+Except operations allow you to return rows from one query that do not appear
+in another query. Except queries are created by composing one or more select
+queries together:
+
+```php
+$allArticles = $articles->find();
+
+$published = $articles->find()
+    ->where(['published' => true]);
+
+$allArticles->except($published);
+```
+
+You can create `EXCEPT ALL` queries using the `exceptAll()` method:
+
+```php
+$allArticles = $articles->find();
+
+$published = $articles->find()
+    ->where(['published' => true]);
+
+$allArticles->exceptAll($published);
+```
+
+`EXCEPT ALL` is supported on PostgreSQL and recent MySQL/MariaDB versions.
+It is not supported on SQLite or SQL Server.
+
+::: info Added in version 5.4.0
+`except()` and `exceptAll()` were added.
+:::
+
 ### Subqueries
 
 Subqueries enable you to compose queries together and build conditions and