Question

我有一个相当简单的查询，当我在phpMyAdmin中测试它时运行正常：

   SELECT   
        c.customers_id,
        c.customers_cid,
        c.customers_gender,
        c.customers_firstname,
        c.customers_lastname,
        c.customers_email_address,
        c.customers_telephone,
        c.customers_date_added,
        ab.entry_company,
        ab.entry_street_address,
        ab.entry_postcode, 
        ab.entry_city,
        COUNT(o.customers_id) AS orders_number,
        SUM(ot.value) AS totalvalue, 
        mb.bonus_points
   FROM     
        orders AS o,
        orders_total AS ot,
        customers AS c, 
        address_book AS ab, 
        module_bonus AS mb
   WHERE 
        c.customers_id = o.customers_id 
        AND c.customers_default_address_id = ab.address_book_id 
        AND c.customers_id = mb.customers_id    
        AND o.orders_id = ot.orders_id 
        AND ot.class = 'ot_subtotal'    
 **  AND c.customers_gender  = 'm' AND c.customers_lastname LIKE 'Famlex'
    GROUP BY o.customers_id

标有**的行会根据进行查询的应用程序的过滤设置而改变。

现在，当我在phpMyAdmin中测试时，查询需要几秒钟才能运行（这很好，因为有数千个条目，据我所知，当使用COUNTs和SUMs索引时没有帮助并且结果是完美的，但是当我在PHP中运行完全相同的查询（在运行之前回显）时，MySQL线程将核心加载到100％并且直到我杀死它才停止。

如果我删除额外的东西来计算COUNT和SUM，查询结束但结果对我来说没用。

说明：

1   SIMPLE  mb  ALL     NULL                        NULL        NULL        NULL                                48713       Using temporary; Using filesort
1   SIMPLE  ot  ALL     idx_orders_total_orders_id  NULL        NULL        NULL                                811725      Using where
1   SIMPLE  o   eq_ref  PRIMARY                     PRIMARY     4           db.ot.orders_id                     1           Using where
1   SIMPLE  c   eq_ref  PRIMARY                     PRIMARY     4           db.o.customers_id                   1           Using where
1   SIMPLE  ab  eq_ref  PRIMARY                     PRIMARY     4           db.c.customers_default_address_id   1

应用索引并使用连接后

EXPLAIN：

1   SIMPLE  c   ref     PRIMARY,search_str_idx              search_str_idx          98      const                                   1       Using where; Using temporary; Using filesort
1   SIMPLE  mb  ALL     NULL                                NULL                    NULL    NULL                                    48713   Using where
1   SIMPLE  ab  eq_ref  PRIMARY                             PRIMARY                 4       db.c.customers_default_address_id       1    
1   SIMPLE  ot  ref     idx_orders_total_orders_id,class    class                   98      const                                   157004  Using where
1   SIMPLE  o   eq_ref  PRIMARY                             PRIMARY                 4       db.ot.orders_id                         1       Using where

Answer 1

使用显式连接而不是隐式

SELECT  
c.customers_id,
c.customers_cid,
c.customers_gender,
c.customers_firstname,
c.customers_lastname,
c.customers_email_address,
c.customers_telephone,
c.customers_date_added,
ab.entry_company,
ab.entry_street_address,
ab.entry_postcode, 
ab.entry_city,
COUNT(o.customers_id) AS orders_number,
SUM(ot.value) AS totalvalue, 
mb.bonus_points
FROM    
orders o 
join orders_total ot on o.orders_id = ot.orders_id 
join customers c on c.customers_id = o.customers_id 
join address_book ab on c.customers_default_address_id = ab.address_book_id 
join module_bonus mb on c.customers_id = mb.customers_id 
where
ot.class = 'ot_subtotal'
c.customers_gender  = 'm' 
AND c.customers_lastname = 'Famlex'
GROUP BY o.customers_id

假设所有连接键也是这些表的主键，即：

o.orders_id, c.customers_id, ab.address_book_id

如果尚未添加以下索引，则需要添加以下索引

alter table  orders add index customers_id_idx(customers_id);
alter table module_bonus add index customers_id_idx(customers_id);
alter table orders_total add index orders_id_idx(orders_id);
alter table orders_total add index orders_class_idx(class);
alter table customers add index search_str_idx(customers_gender,customers_lastname);

确保在应用索引之前备份表。

Answer 2

你能分享你的记录的SQL转储，以便我可以看看吗？

phpMyAdmin自动将限制条款添加到选择查询，这就是为什么我认为你在phpMyAdmin查询运行正常但不通过PHP脚本的印象。尝试在运行之前向phpMyAdmin中的查询说限制0,1000添加显式限制子句，看看是否会使phpMyAdmin的性能变慢。

MySQL查询在phpMyAdmin中运行正常，但在PHP中挂起

2 个答案: