php - 尝试在mysql查询中显示最大时间记录

Question

我目前正在构建一个 Mysql 数据库，用于处理锂电池充电器的充电-放电日志，我需要从我的电池充电信息中显示以下内容

`1B     LG HG2 18650    103     00:00:00    0.001   3.042   0   22.1`
`1B     LG HG2 18650    103     00:30:00    0.5     3.442   175.2   23.5`
`1B     LG HG2 18650    103     01:00:00    0.5     3.53    425.4   24.2`
`1B     LG HG2 18650    103     01:30:00    0.5     3.627   675.5   24.7`
`1B     LG HG2 18650    103     02:00:00    0.5     3.683   925.7   24.7`
`1B     LG HG2 18650    103     02:30:00    0.5     3.757   1175.8  25`
`1B     LG HG2 18650    103     03:00:00    0.5     3.851   1426    25.2`
`1B     LG HG2 18650    103     03:30:00    0.5     3.939   1676.1  25`
`1B     LG HG2 18650    103     04:00:00    0.5     4.02    1926.3  25.2`
`1B     LG HG2 18650    103     04:30:00    0.5     4.107   2176.5  24.7`
`1B     LG HG2 18650    103     05:00:00    0.5     4.147   2426.6  24.7`

(直到 5 小时标记为止每 30 分钟间隔的具体数据) 现在我想合并充电周期的最后一个日志条目。我在 where 中添加了另一个 or 子句并选择了最大时间

    SELECT 
    `Cell`, 
    `Cell_Make_Model` as `CEll Make And Model`, 
    `Charge_number` as `Charge Number`, 
    `Time_in_charge` as `Charge Clock`, 
    `Current` as `Charge Current`, 
    `Voltage` as `Cell Voltage`, 
    `Capacity` as `Charging Capacity`, 
    `Cell_Temp` as `Cell Temperature (In Celsius)` 
FROM 
    `Cell_Charge_Info` as a 
    INNER JOIN Cell_Make_And_Model b on a.cell = b.Cell_Code 
WHERE 
    b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 0 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 1800 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 3600 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 5400 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 7200 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 9000 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 10800 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 12600 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 14400 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 16200 
    or b.Cell_Make_Model like "LG HG2 18650" 
    AND time_to_sec(`Time_in_charge`)= 18000 
    or a.Time_in_charge = (
        select 
            max(c.Time_in_charge)
        from 
            Cell_Charge_Info as c 
        where 
            c.cell = a.cell 
            and c.Charge_number = a.Charge_number
            and c.time_in_charge=max(a.time_in_Charge))

当我在 phpMyAdmin 中执行它时，系统挂起，并且 mysqld 进程的 CPU 利用率为 100%。 如果我从查询中删除最后一个或选择，它的功能齐全，但结果集不包含费用的最后一个日志条目。 任何帮助将不胜感激。

Answer 1

这并不能解决问题 - 但它肯定更容易阅读......

SELECT Cell
     , Cell_Make_Model  `Cell Make And Model`
     , Charge_number    `Charge Number`
     , Time_in_charge   `Charge Clock`
     , Current          `Charge Current`
     , Voltage          `Cell Voltage`
     , Capacity         `Charging Capacity`
     , Cell_Temp        `Cell Temperature (In Celsius)`
  FROM Cell_Charge_Info a 
  JOIN Cell_Make_And_Model b 
    ON b.Cell_Code = a.cell 
 WHERE (b.Cell_Make_Model = "LG HG2 18650" AND TIME_TO_SEC(Time_in_charge) IN(0,1800,3600,5400,7200,9000,10800,12600,14400,16200,18000)) 
    OR a.Time_in_charge = (SELECT MAX(c.Time_in_charge)
                             FROM Cell_Charge_Info c      
                            WHERE c.cell = a.cell 
                              AND c.Charge_number = a.Charge_number
                              AND c.time_in_charge = MAX(a.time_in_Charge)
                          );