Question

我创建了一个查询，它从两个表中收集数据，对它们进行求和，并显示案例的数量和总和：

SELECT
    count(ut.id) AS total
    , ( SUM(internal_account) - SUM(( SELECT
            SUM( ub.bill_summs )
        FROM
            u_billing ub
        WHERE
            ub.bill_types = 'correction'
            AND ub.contract_id = ut.contract_id
      )) ) AS summ
FROM  
    u_transactions ut
WHERE
    ut.nulled = 0
    AND ut.type = 'comission'
    AND ut._status = 'not_paid'
    AND DATE( ut.add_timestamp ) = DATE( '2012-05-11' );

但它真的很慢。在测试用例中，它给出了这个结果：

+-------+-------+
| total | summ  |
+-------+-------+
|   182 | 15105 |
+-------+-------+
1 row in set (4.13 sec)

在182个案例中只有4.13秒而且只有1天，但我的实时服务器有超过600k的案例，所以这将非常慢。

任何想法，我如何重写查询以获得更好的性能？

重新构建查询的解决方案：

DELETE FROM tmpContractSums;
INSERT INTO tmpContractSums
SELECT
    ub.contract_id
    , SUM( ub.bill_summs ) AS bill_summs
FROM
    u_billing ub
WHERE
    ub.bill_types = 'correction'
GROUP BY ub.contract_id;

SELECT
    count(ut.id) AS total
    , ( SUM(internal_account) - SUM(bill_summs) )
FROM  
    u_transactions ut
LEFT JOIN tmpContractSums t ON ut.contract_id = t.contract_id
WHERE
    ut.nulled = 0
    AND ut.type = 'comission'
    AND ut._status = 'not_paid'
    AND ut.add_timestamp BETWEEN '2012-05-11 00:00:00' AND '2012-05-11 23:59:59';

执行时间： 500ms

PS：因为我不能用webuser删除表，所以我刚刚创建了表：

CREATE TABLE tmpContractSums AS SELECT contract_id, bill_summs FROM u_billing WHERE 1 = 0;

我正在删除记录。没有下降那么快，但仍然比原来快。

Answer 1

如何简单地使用“临时”表？

DROP TABLE IF EXISTS tmpContractSums;
CREATE TABLE tmpContractSums AS SELECT contract_id, bill_summs FROM u_billing WHERE 1 = 0;
INSERT INTO tmpContractSums
SELECT
    ub.contract_id
    SUM( ub.bill_summs ) AS bill_summs
FROM
    u_billing ub
WHERE
    ub.bill_types = 'correction'
GROUP BY ub.contract_id;

SELECT
    count(ut.id) AS total
    , ( SUM(internal_account) - COALESCE(bill_summs, 0) )
FROM  
    u_transactions ut
LEFT JOIN tmpContractSums t ON ut.contract_id = t.contract_id
WHERE
    ut.nulled = 0
    AND ut.type = 'comission'
    AND ut._status = 'not_paid'
    AND ut.add_timestamp BETWEEN '2012-05-11' AND '2012-05-11 23:59:59';

这应该更快，如果你想要，你可以添加索引到“临时表”，或者如果你有足够的空间，可以使它成为一个带有engine = memory的表。

或者：

DROP TABLE IF EXISTS tmpContractSums;
CREATE TABLE tmpContractSums AS SELECT contract_id, bill_summs FROM u_billing WHERE 1 = 0;
INSERT INTO tmpContractSums
SELECT
    ub.contract_id
    SUM( ub.bill_summs ) AS bill_summs
FROM
    u_billing ub
WHERE
    ub.bill_types = 'correction'
GROUP BY ub.contract_id;

SELECT
    count(ut.id) AS total
    , ( SUM(internal_account) - (SELECT bill_summs FROM tmpContractSums t WHERE ut.contract_id = t.contract_id ) )
FROM  
    u_transactions ut
WHERE
    ut.nulled = 0
    AND ut.type = 'comission'
    AND ut._status = 'not_paid'
    AND ut.add_timestamp BETWEEN '2012-05-11' AND '2012-05-11 23:59:59';

Answer 2

希望这有帮助

    SELECT 
        COUNT(A.id) AS total,
        (SUM(A.internal_account) - SUM(COALESCE(B.bill_sums, 0)) AS 'Sum'
    FROM
    u_transactions A
    LEFT JOIN u_billing B on A.contract_id = B.contract_id
    WHERE 
    A.nulled = 0 AND
    A.type = 'comission' AND
    A._status = 'not_paid' AND
    DATE(A.add_timestamp) = DATE('2012-05-11')
    AND B.bill_types = 'correction';

编辑：

我没有注意到你对子查询的结果求和。：

SELECT
    count(ut.id) AS total
    , ( SUM(internal_account) - **SUM**(( SELECT
            **SUM**( ub.bill_summs )
        FROM
            u_billing ub
        WHERE
            ub.bill_types = 'correction'
            AND ub.contract_id = ut.contract_id
      )) ) AS summ
FROM  
    u_transactions ut

也许你可以用合并来代替总和：

-COALESCE(( SELECT
        **SUM**( ub.bill_summs )
    FROM
        u_billing ub
    WHERE
        ub.bill_types = 'correction'
        AND ub.contract_id = ut.contract_id
  ),0)

Answer 3

不是吗？我的意思是它必须更好地工作。

SELECT
    count(ut.id) AS total
    , SUM(internal_account - COALESCE(ub.b_summs, 0)) summ
FROM u_transactions ut
    LEFT JOIN 
        (
            SELECT 
                contract_id,
                SUM(bill_summs) b_summs
            FROM u_billing
            WHERE bill_types = 'correction'
            GROUP BY contract_id
        ) AS ub
        ON ub.contract_id = ut.contract_id
WHERE
    ut.nulled = 0
    AND ut.type = 'comission'
    AND ut._status = 'not_paid'
    AND DATE( ut.add_timestamp ) = DATE( '2012-05-11' );

此外，您必须避免在应用于表列的WHERE子句上使用函数。如果你有索引，使用函数不允许索引使用。请改用：

AND ut.add_timestamp >= DATE( '2012-05-11' ) AND ut.add_timestamp < DATE( '2012-05-12' );

Answer 4

这应该可以加快速度：

SELECT 
   COUNT(ua.id) as total,
   SUM(ua.internal_account - ua.corrections) as 'sum'
FROM (  
    SELECT 
       ut.id,
       ut.internal_account,
       SUM(COALESCE(ub.bill_sums, 0)) AS corrections
    FROM
       u_transactions ut
          LEFT JOIN u_billing ub on ut.contract_id = ub.contract_id
    WHERE 
       ut.nulled = 0 AND
       ut.type = 'comission' AND
       ut._status = 'not_paid' AND
       DATE(ub.add_timestamp) = DATE('2012-05-11') AND 
       ut.bill_types = 'correction'
    GROUP BY
       ut.id
    ) as ua

修改：更正add_timestamp表格前缀并插入缺失的GROUP BY

创建一个总结两个表的更好的查询

4 个答案: