数据库查询执行时间过长

Question

当前遇到这样的问题，我的数据库查询执行时间太长，有时最终失败并报错：超过了最大执行时间...我试图从彼此不直接相关的不同表中选择数据一个表与另一个表相关，依此类推，其中一些表有上千条记录，我感到不同表的结构导致了这种麻烦，但我无法弄清楚了解如何减少执行时间。 我正在使用CodeIgniter模型，其中我使用以下sql查询创建了一个函数：

/**
* Get payment history based on search term
* @param string $search
* @param int $limt => default is 10
* @return mixed
**/

public function get_search_history($usertin, $search, $limit, $offset){

    $this->db->select("
            rv.name AS 'Revenue Name',rv.code AS 'Rev. Code',
            m.name AS 'MDA',m.sector AS 'Sector', b.code AS 'Bank Code',
            b.name AS 'Bank',p.amount AS 'Amount',p.channel AS 'Payment Channel',
            p.date AS 'Payment Date',p.platform AS 'Platform',p.ref AS 'Reference',
            t.tin AS 'TIN',t.active AS 'Is Active?',r.ref AS 'Receipt Reference'
        ");

    $this->db->from('revenue AS rv');
    $this->db->join('mda AS m', 'm.id = rv.mda_id', 'inner');
    $this->db->join('payment AS p', 'p.revenue_id = rv.id', 'inner');
    $this->db->join('bank AS b', 'b.id = p.bank_id', 'inner');
    $this->db->join('tin AS t', 't.id = p.tin_id', 'inner');
    $this->db->join('receipt AS r', 'r.id = p.receipt', 'inner');
    $this->db->where('t.tin', $usertin);
    $this->db->like('rv.code', $search);
    $this->db->or_like('rv.name', $search);
    $this->db->or_like('m.name', $search);
    $this->db->group_by('t.id');
    $this->db->order_by('p.date', 'ASC');
    $this->db->limit($limit, $offset);

    $query = $this->db->get();

    return ( ( $query->num_rows() > 0 ) ? $query->result_array() : 0 );

}

该查询应该基于特定的搜索词或关键字来检索用户的付款历史！

从上面的查询中可以更容易看出我说“ ...一个表与另一个表相关的表...”的含义。我只是想不出一种更好的方法。 谁能帮我吗？ 这几天让我头疼不已！

这是查询的输出：

SELECT rv.name AS 'Revenue Name', rv.code AS 'Rev. Code', m.name AS
'MDA', m.sector AS 'Sector', b.code AS 'Bank Code', b.name AS 'Bank',
p.amount AS 'Amount', p.channel AS 'Payment Channel', p.date AS 'Payment
Date', p.platform AS 'Platform', p.ref AS 'Reference', t.tin AS 'TIN',
t.active AS 'Is Active?', r.ref AS 'Receipt Reference'
FROM `revenue` AS `rv`
INNER JOIN `mda` AS `m` ON `m`.`id` = `rv`.`mda_id`
INNER JOIN `payment` AS `p` ON `p`.`revenue_id` = `rv`.`id`
INNER JOIN `bank` AS `b` ON `b`.`id` = `p`.`bank_id`
INNER JOIN `tin` AS `t` ON `t`.`id` = `p`.`tin_id`
INNER JOIN `receipt` AS `r` ON `r`.`id` = `p`.`receipt`
WHERE `t`.`tin` = '1904260529-0001'
AND  `rv`.`code` LIKE '%With%' ESCAPE '!'
OR  `rv`.`name` LIKE '%With%' ESCAPE '!'
OR  `m`.`name` LIKE '%With%' ESCAPE '!'
GROUP BY `t`.`id`
ORDER BY `p`.`date` ASC
LIMIT 3, 20

Answer 1

如果您有这么多的表要经常连接，我建议有2种可能的方法。

1.使用CodeIgniter的功能查询缓存

• 您只需要从database.php启用它，并给它提供所有高速缓存的查询所在的文件夹路径。
• 然后，您可以创建挂钩或某些要删除的东西，并在特定条件下重新生成缓存的查询。

2.在MySQL中创建视图

• 您可以在MySQL中创建View ，它将更快。 甚至可以从PHPMyAdmin轻松完成。

希望这可以帮助。

ps尝试索引适当的列。

简单的经验法则是WHERE子句中的条件越多，查询越低