Question

我希望(`Pre-Scan Hours Planned`-`Pre-Scan Time Spent`)只是积极的。如果结果是否定的，我不想要它。我在SELECT子句中尝试了(`Pre-Scan Hours Planned`-`Pre-Scan Time Spent`)>0但它没有用。

 SELECT 

        `Account Executive`,
        `DC Clerk`,
        `Project Number`,
        Manufacturer,
        `Open Project Date`,
        `DUE DATE`,
        `Project Status`,

       ( `Pre-Scan Hours Planned`+
        `Radiated Emissions Hours Planned`+
        `Conducted Emissions Hours Planned`+
        `Harmonic and Flicker Hours Planned`+
        `ESD Hours Planned`+
        `RF Immunity Hours Planned`+
        `EFT Hours Planned`+
        `Surge Hours Planned`+
        `Conducted RF Hours Planned`+
        `Magnetic Field Hours Planned`+
        `Voltage Dips Hours Planned`+
        `EUT Photos and Data Sheet Hours Planned`+
        `Data Sheet Hours Planned` ) AS 'Total Planned Hours',

       ( `Pre-Scan Time Spent`+
        `Radiated Emissions Time Spent`+
        `Conducted Emissions Time Spent`+
        `Harmonic and Flicker Time Spent`+
        `ESD Time Spent`+
        `RF Immunity Time Spent`+
        `EFT Time Spent`+
        `Surge Time Spent`+
        `Conducted RF Time Spent`+
        `Magnetic Field Time Spent`+
        `Voltage Dips Time Spent`+
        `EUT Photos and Data Sheet Time Spent`+
        `Data Sheet Time Spent` ) AS 'Total Spent Hours',

        ( (`Pre-Scan Hours Planned`-`Pre-Scan Time Spent`)+
        (`Radiated Emissions Hours Planned`-`Radiated Emissions Time Spent`) +
        (`Conducted Emissions Hours Planned`-`Conducted Emissions Time Spent`) +
        (`Harmonic and Flicker Hours Planned`-`Harmonic and Flicker Time Spent`) +
        (`ESD Hours Planned`-  `ESD Time Spent`) +
        (`RF Immunity Hours Planned`-`RF Immunity Time Spent`) +
        (`EFT Hours Planned`-  `EFT Time Spent`) +
        (`Surge Hours Planned`-`Surge Time Spent`) +
        (`Conducted RF Hours Planned`-`Conducted RF Time Spent`) +
        (`Magnetic Field Hours Planned`-`Magnetic Field Time Spent`)+
        (`Voltage Dips Hours Planned`-`Voltage Dips Time Spent`) +
        (`EUT Photos and Data Sheet Hours Planned`-`EUT Photos and Data Sheet Time 
        Spent`) +
        (`Data Sheet Hours Planned` -`Data Sheet Time Spent`)) AS 'Remaining Hours',

        (`Pre-Scan Status`+
        `Radiated Emissions Status`+
        `Conducted Emissions Status`+
        `Harmonic and Flicker Status`+
        `ESD Status`+
        `RF Immunity Status`+
        `EFT Status`+
        `Surge Status`+
        `Conducted RF Status`+
        `Magnetic Field Status`+
        `Voltage Dips Status`+
        `EUT Photos Status`+
        `Data Sheet Status`) AS 'Items Remaining'

    FROM 
        EMCtestplan

让我更好地解释，例如我们有以下查询：

我需要这个：

select
a,
b,
c,
(f1-f2)+(f3-f4)+(f5-f6) as Sum
from table

我希望(f1-f2)+(f3-f4)+(f5-f6) as Sum此代码只计算正数公式。例如，如果(f3-f4)是negetive并且只是计算(f1-f2)+(f5-f6)

，则不计算总和

请有人帮帮我！

Answer 1

更改为OP提出的新问题的答案

OP有：

select
a,
b,
c,
(f1-f2)+(f3-f4)+(f5-f6) as Sum
from table

我希望（f1-f2）+（f3-f4）+（f5-f6）为Sum此代码只计算积极的公式。例如，如果（f3-f4）是，则不计算总和 negetive和just calculte（f1-f2）+（f5-f6）

如果您只关心（f3-f4）否定：

select
a,
b,
c,
CASE 
    When (f3-f4) < 0 then (f1-f2)+(f5-f6)
    Else (f1-f2)+(f3-f4)+(f5-f6)
END as Sum
from table

如果担心（f1-f2），（f3-f4），（f5-f6）中的任何一个是负数，那么我会处理不同的

select
a,
b,
c,
(MAX(f1-f2,0) + MAX(f3-f4,0) + MAX(f5-f6,0) as Sum
from table

Answer 2

负面时你想用什么？我假设你想要使用零。变化：

(`Pre-Scan Hours Planned`-`Pre-Scan Time Spent`)

为：

(CASE WHEN `Pre-Scan Hours Planned`-`Pre-Scan Time Spent` > 0
      THEN (`Pre-Scan Hours Planned`-`Pre-Scan Time Spent`)
      ELSE 0 END)

如果您愿意，可以使用零以外的其他内容。

如何仅从MySQL查询中获得积极结果？

2 个答案: