Question

我查看并尝试了许多不同的解决方案，但似乎没有一个可行。我正在运行以下查询以从100k表中获取结果：

SELECT * FROM (SELECT expenses.id AS eID, expenses.date, 
                        expenses.receipt, expenses.purpose, expenses.date_submitted, 
                        expenses.expense_type, expenses.description, 
                        expenses.curr_used,expenses.reimbursement_amount, 
                        expenses.hst_amount, expenses.amex_amount, expenses.gl_acct, 
                        expenses.net_amount,expenses.status, users.id AS uID,  
                        users.firstname, users.lastname, users.department, 
                        users.adminship_level, users.is_finance 
                FROM expenses 
                    INNER JOIN users on expenses.user_id = users.id
            )  as expense_info 
WHERE (
        (department="Publishing" 
        AND adminship_level < 4) 
    OR uID=8
    ) 
ORDER BY date_submitted DESC 
LIMIT 15

支出表是具有10万行的表，而用户表有500个用户。

users表与带user_id外键的费用相关联，并且还包含部门+行政级别的复合索引。

解释收益the following

使用MySQL Workbench运行此程序效果很好，并且速度非常快。但是，将完全相同的查询放入php并使用PDO的prepare（）+ execute（）函数需要6整秒钟来获取15个结果。

关于如何提高速度的任何想法？我在做什么错了？

我正在使用XAMPP，但没有使用它的MariaDB（相反，我使用的是MySQL 8）

请询问可能有帮助的其他详细信息，我会提供

Answer 1

Erm，

SELECT e.id eID
     , e.date
     , e.receipt
     , e.purpose
     , e.date_submitted
     , e.expense_type
     , e.description
     , e.curr_used
     , e.reimbursement_amount
     , e.hst_amount
     , e.amex_amount
     , e.gl_acct
     , e.net_amount
     , e.status
     , u.id uID
     , u.firstname
     , u.lastname
     , u.department
     , u.adminship_level
     , u.is_finance 
  FROM expenses e
  JOIN users u
    ON e.user_id = u.id
 WHERE (u.department = "Publishing" AND u.adminship_level < 4) 
    OR uID=8
 ORDER 
    BY e.date_submitted DESC 
 LIMIT 15

Answer 2

这似乎是您需要做的，除去不必要的子查询及其开销

SELECT expenses.id AS eID, expenses.date, 
       expenses.receipt, expenses.purpose, expenses.date_submitted, 
       expenses.expense_type, expenses.description, 
       expenses.curr_used,expenses.reimbursement_amount, 
       expenses.hst_amount, expenses.amex_amount, expenses.gl_acct, 
       expenses.net_amount,expenses.status, users.id AS uID,  
       users.firstname, users.lastname, users.department, 
       users.adminship_level, users.is_finance 
FROM expenses 
    INNER JOIN users on expenses.user_id = users.id
WHERE uID = :uID
OR (department="Publishing" AND adminship_level < :aship)
ORDER BY date_submitted DESC 
LIMIT 15

PDO查询运行缓慢

2 个答案: