Question

我有3张订单表。

1-) orders

orderID ⎜odate ⎜ fullname ⎜address ⎜ ordersum ⎜ status_id

2-) order_products

id ⎜orderID ⎜count⎜ psum ⎜cost

3-) order_sum

orderID ⎜shipping ⎜tax ⎜coupon ⎜ discount

按照以下顺序，我按日期获得“折扣/订单价值/产品总数/税额”。但是对于20000条记录，查询需要12秒。我该如何优化呢？

SELECT
    DATE(o.odate) AS ODate,
    COUNT(o.orderID) AS OTotal,
    (
        SELECT
            SUM(op.psum)
        FROM
            order_products op
        INNER JOIN orders oo ON oo.orderID = op.orderID
        WHERE
            DATE(oo.odate) = DATE(o.odate)
        AND oo.status_id NOT IN (24, 26, 27, 28, 29)
    ) AS ProductSum,
    SUM(os.shipping) / 118 * 100 AS Shipping,
    SUM(os.tax) AS Tax,
    SUM(o.ordersum) AS allPayments,
    SUM(os.coupon) AS CouponDiscount,
    SUM(os.discount) AS Discount,
    (
        SUM(o.ordersum) / COUNT(DISTINCT o.orderID)
    ) AS BasketAVG
FROM
    orders o
JOIN order_sum os ON os.orderID = o.orderID
WHERE
    o.status_id NOT IN (24, 26, 27, 28, 29)
AND o.odate BETWEEN '2014-12-01'
AND '2014-12-30'
GROUP BY
    DATE(o.odate)
ORDER BY
    o.odate ASC;

Exlpand：

+----+--------------------+-------+--------+-----------------+-----------+---------+-----------------------------+-------+----------------------------------------------+
| id | select_type        | table | type   | possible_keys   | key       | key_len | ref                         | rows  | Extra                                        |
+----+--------------------+-------+--------+-----------------+-----------+---------+-----------------------------+-------+----------------------------------------------+
|  1 | PRIMARY            | o     | ALL    | PRIMARY,orders  | NULL      | NULL    | NULL                        | 10645 | Using where; Using temporary; Using filesort |
|  1 | PRIMARY            | os    | eq_ref | PRIMARY,ordersum| PRIMARY   | 4       | cikolat_system.o.orderID    |     1 |                                              |
|  2 | DEPENDENT SUBQUERY | oo    | ALL    | PRIMARY,orders  | NULL      | NULL    | NULL                        | 10645 | Using where                                  |
|  2 | DEPENDENT SUBQUERY | op    | ref    | oproducts2      | oproducts2| 5       | cikolat_system.oo.orderID   |     1 | Using where                                  |
+----+--------------------+-------+--------+-----------------+-----------+---------+-----------------------------+-------+----------------------------------------------+

SQLFiddle：http://sqlfiddle.com/#!2/81c921/1

Answer 1

我建议你抛弃SELECT列表中的相关子查询，并使用连接操作进行内联视图。我会写这样的查询：

SELECT DATE(o.odate)                AS ODate
     , COUNT(o.orderID)             AS OTotal
     , ps.ProductSum                AS ProductSum
     , SUM(os.shipping) / 118 * 100 AS Shipping
     , SUM(os.tax)                  AS Tax
     , SUM(o.ordersum)              AS allPayments
     , SUM(os.coupon)               AS CouponDiscount
     , SUM(os.discount)             AS Discount
     , SUM(o.ordersum)
       / COUNT(DISTINCT o.orderID)  AS BasketAVG
  FROM orders o
  JOIN order_sum os
    ON os.orderID = o.orderID
  LEFT
  JOIN ( SELECT op.orderID
              , SUM(op.psum) AS ProductSum
           FROM order_products op
          GROUP BY op.orderID 
       ) ps
    ON ps.orderID = o.orderID
 WHERE o.status_id NOT IN (24, 26, 27, 28, 29)
   AND o.odate BETWEEN '2014-12-01' AND '2014-12-30'
 GROUP BY DATE(o.odate)
 ORDER BY DATE(o.odate) ASC

解释输出将显示派生表;使用MySQL 5.5及更早版本，将无法编制索引。

如果从orders表中检索的行是整个表的一小部分，那么orders表上的适当索引可能允许MySQL使用索引范围扫描操作：

... ON orders (odate, status)

而且，如果这是表中的一小部分行，那么内联视图查询中的JOIN操作将产生一个小得多的派生表，这可能会提高性能。在内联视图查询中的orders表上重复谓词，例如：

  LEFT
  JOIN ( SELECT op.orderID
              , SUM(op.psum) AS ProductSum
           FROM order_products op
           JOIN orders oo
             ON oo.orderID = op.orderID
          WHERE oo.status_id NOT IN (24, 26, 27, 28, 29)
            AND oo.odate BETWEEN '2014-12-01' AND '2014-12-30'
          GROUP BY op.orderID
       ) ps

此外，order_products上的覆盖索引将允许MySQL完全从索引中满足视图查询（EXPLAIN将显示“使用索引”）

... ON order_products (orderID, psum)

（如果odate列的数据类型为DATE，则不需要DATE（）包装函数，MySQL可以避免使用“使用filesort”。如果数据类型是DATETIME或TIMESTAMP数据类型，则说明使用DATE（）包装函数。请注意，odate列上的谓词将返回值，该值的值在当月的第一个午夜之间，直到当月30日的午夜。通常，我们只会返回整天，避免排除30日午夜。

   AND o.odate >= '2014-12-01 00:00:00'
   AND o.odate <  '2014-12-30 00:00:00'

（我在文字值中添加时间组件是不必要的;只是为了说明在比较日期时间或时间戳时考虑时间组件的想法。）

SQL优化 - 3个表 - 多个SUM - 20k记录 - 12秒

1 个答案: