支持 MySQL 高性能分页查询（大表分页类）

doc/components/db/index.md

@@ -722,6 +722,30 @@ var_dump(json_encode($data)); // 支持序列化
 ]
 ```
 
+### 高性能分页查询
+
+```php
+// 首先准备好查询构建器
+$query = Db::query()->from('xxxtable');
+
+// 实例化大表分页类，字段名默认 id
+$pagination = new \Imi\Db\Mysql\Query\Pagination\BigTablePagination($query);
+// 指定主表主键字段名，如果涉及多张表关联，这里需要指定主表的主键字段名
+$pagination = new \Imi\Db\Mysql\Query\Pagination\BigTablePagination($query, 'xxxtable.id');
+
+// 只查列表，返回值同 $query->select()，Result 对象
+$result = $pagination->select();
+// 获取数组
+$result->getArray();
+
+// 分页查询，返回值同 $query->paginate()，PaginationResult 对象
+$page = 1;
+$limit = 10;
+$result = $pagination->paginate($page, $limit);
+```
+
+> 仅 MySQL 数据库支持
+
 ## 查询执行
 
 ### 查询记录

src/Db/Mysql/Query/Pagination/BigTablePagination.php

+<?php
+
+declare(strict_types=1);
+
+namespace Imi\Db\Mysql\Query\Pagination;
+
+use Imi\Db\Query\Interfaces\IPaginateResult;
+use Imi\Db\Query\Interfaces\IQuery;
+use Imi\Db\Query\Interfaces\IResult;
+use Imi\Db\Query\PaginateResult;
+use Imi\Util\Pagination;
+
+class BigTablePagination
+{
+    protected IQuery $query;
+
+    protected string $idField = '';
+
+    public function __construct(IQuery $query, string $idField = 'id')
+    {
+        $this->query = $query;
+        $this->idField = $idField;
+    }
+
+    public function getQuery(): IQuery
+    {
+        return $this->query;
+    }
+
+    public function paginate(int $page, int $limit, array $options = []): IPaginateResult
+    {
+        if ($options['total'] ?? true)
+        {
+            $query = clone $this->query;
+            $option = $query->getOption();
+            $option->order = [];
+            $total = (int) $query->count();
+        }
+        else
+        {
+            $total = null;
+        }
+        $pagination = new Pagination($page, $limit);
+        $query = clone $this->query;
+
+        return new PaginateResult($this->select($page, $limit), $pagination->getLimitOffset(), $limit, $total, null === $total ? null : $pagination->calcPageCount($total), $options);
+    }
+
+    public function select(int $page, int $limit): IResult
+    {
+        $query = clone $this->query;
+        $ids = $query->field($this->idField)->page($page, $limit)->select()->getColumn();
+        $query = clone $this->query;
+
+        return $query->whereIn($this->idField, $ids)->select();
+    }
+}

tests/unit/Component/Tests/Db/QueryCurdBaseTest.php

@@ -8,6 +8,7 @@ use Imi\Db\Db;
 use Imi\Db\Mysql\Query\FullText\MysqlFullTextOptions;
 use Imi\Db\Mysql\Query\FullText\SearchModifier;
 use Imi\Db\Mysql\Query\Lock\MysqlLock;
+use Imi\Db\Mysql\Query\Pagination\BigTablePagination;
 use Imi\Db\Query\Database;
 use Imi\Db\Query\Raw;
 use Imi\Db\Query\Where\Where;
@@ -187,6 +188,37 @@ abstract class QueryCurdBaseTest extends BaseTest
         $this->assertEquals($expectedData['page_count'], $result->getPageCount());
     }
 
+    /**
+     * @depends testInsert
+     */
+    public function testBigTablePagination(array $args): void
+    {
+        ['ids' => $ids] = $args;
+        $expectedData = [
+            'list'          => [
+                [
+                    'id'        => $ids[1],
+                    'title'     => 'title-insert',
+                    'content'   => 'content-insert',
+                    'time'      => '2019-06-21 00:00:00',
+                    'member_id' => 0,
+                ],
+            ],
+            'limit'         => 1,
+            'total'         => 2,
+            'page_count'    => 2,
+        ];
+        $query = Db::query($this->poolName)->from($this->tableArticle);
+        $pagination = new BigTablePagination($query);
+        $this->assertEquals($expectedData, $pagination->select(2, 1)->getArray());
+        $result = $pagination->paginate(2, 1);
+        $this->assertEquals($expectedData, $result->toArray());
+        $this->assertEquals($expectedData['list'], $result->getList());
+        $this->assertEquals($expectedData['total'], $result->getTotal());
+        $this->assertEquals($expectedData['limit'], $result->getLimit());
+        $this->assertEquals($expectedData['page_count'], $result->getPageCount());
+    }
+
     /**
      * @depends testInsert
      *