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不忽略MySQL行
EN

Stack Overflow用户
提问于 2015-03-29 04:28:49
回答 1查看 36关注 0票数 0

我的结果是以我想要的方式返回--我只想忽略MPG_VALUE > 30 (nvdtechnical.TECH_Value_Float)的行

但是,我的查询返回MPG_VALUE列中的所有行和不需要的行都为空。

如何只返回MPG_VALUE > 30的行?

代码语言:javascript
复制
SELECT *, (SELECT PR_Basic + PR_VAT + PR_Delivery FROM nvdprices 
WHERE PR_Id = capder.cder_ID ORDER BY PR_EffectiveTo ASC LIMIT 1) as P11D,

(SELECT nvdtechnical.TECH_Value_Float FROM nvdtechnical 
 WHERE TECH_TechCode = '11' 
 AND nvdtechnical.TECH_Id = capder.cder_ID
 AND nvdtechnical.TECH_Value_Float > 30 
 LIMIT 1) as MPG_VALUE

from capmod 

JOIN capder ON capder.cder_modcode = capmod.cmod_code 
JOIN caprange ON capder.cder_rancode = caprange.cran_code 
JOIN capman ON caprange.cran_mantextcode = capman.cman_code 
JOIN nvdmodelyear ON capder.cder_ID = MY_Id 

AND nvdmodelyear.MY_EffectiveTo = '0000-00-00 00:00:00' 

JOIN nvdtechnical ON nvdtechnical.TECH_Id = capder.cder_ID
JOIN nvddictionarytechnical ON nvddictionarytechnical.DT_TechCode = nvdtechnical.TECH_TechCode
JOIN nvddictionarycategory ON nvddictionarycategory.DC_CatCode = nvddictionarytechnical.DT_CatCode

AND nvddictionarycategory.DC_CatCode=4 
AND nvddictionarytechnical.DT_TechCode = 67
AND nvdtechnical.TECH_Value_Float >= '255' 

JOIN capfueltype ON capfueltype.cft_code = capder.cder_fueltype 
JOIN nvdbodystyle ON capmod.cmod_bodystyle = nvdbodystyle.bs_code 

WHERE caprange.cran_mantextcode='140' 
AND caprange.cran_code='522' 
AND capder.cder_fueltype='P' 
AND capder.cder_transmission='A' 
AND nvdbodystyle.bs_code='3' 
AND (cmod_discontinued=0 OR cmod_discontinued=2015) 
AND capman.cman_code IN ('1','140','164') 
AND caprange.cran_code IN ('924','126','147','955','965','661') 

ORDER BY P11D, capman.cman_name ASC, caprange.cran_name, capmod.cmod_name 
EN

回答 1

Stack Overflow用户

回答已采纳

发布于 2015-03-29 04:51:43

这是因为您正在对MPG值执行标量查询。实际上,您并不是在筛选要显示或隐藏的行,而是显示与主查询匹配的所有行。

想象一下左联接,这就像你正在做的事情。

代码语言:javascript
复制
SELECT nvdtechnical.TECH_Value_Float FROM nvdtechnical 
 WHERE TECH_TechCode = '11' 
 AND nvdtechnical.TECH_Id = capder.cder_ID
 **AND nvdtechnical.TECH_Value_Float > 30** 
 LIMIT 1

若要正确筛选数据,必须在where条件下再次过滤外部数据:

最简单的方法就是这样。

代码语言:javascript
复制
SELECT *
FROM (
SELECT *, (SELECT PR_Basic + PR_VAT + PR_Delivery FROM nvdprices 
WHERE PR_Id = capder.cder_ID ORDER BY PR_EffectiveTo ASC LIMIT 1) as P11D,

(SELECT nvdtechnical.TECH_Value_Float FROM nvdtechnical 
 WHERE TECH_TechCode = '11' 
 AND nvdtechnical.TECH_Id = capder.cder_ID
 AND nvdtechnical.TECH_Value_Float > 30
 LIMIT 1) as **MPG_VALUE**

from capmod 

JOIN capder ON capder.cder_modcode = capmod.cmod_code 
JOIN caprange ON capder.cder_rancode = caprange.cran_code 
JOIN capman ON caprange.cran_mantextcode = capman.cman_code 
JOIN nvdmodelyear ON capder.cder_ID = MY_Id 

AND nvdmodelyear.MY_EffectiveTo = '0000-00-00 00:00:00' 

JOIN nvdtechnical ON nvdtechnical.TECH_Id = capder.cder_ID
JOIN nvddictionarytechnical ON nvddictionarytechnical.DT_TechCode = nvdtechnical.TECH_TechCode
JOIN nvddictionarycategory ON nvddictionarycategory.DC_CatCode = nvddictionarytechnical.DT_CatCode

AND nvddictionarycategory.DC_CatCode=4 
AND nvddictionarytechnical.DT_TechCode = 67
AND nvdtechnical.TECH_Value_Float >= '255' 

JOIN capfueltype ON capfueltype.cft_code = capder.cder_fueltype 
JOIN nvdbodystyle ON capmod.cmod_bodystyle = nvdbodystyle.bs_code 

WHERE caprange.cran_mantextcode='140' 
AND caprange.cran_code='522' 
AND capder.cder_fueltype='P' 
AND capder.cder_transmission='A' 
AND nvdbodystyle.bs_code='3' 
AND (cmod_discontinued=0 OR cmod_discontinued=2015) 
AND capman.cman_code IN ('1','140','164') 
AND caprange.cran_code IN ('924','126','147','955','965','661') 

ORDER BY P11D, capman.cman_name ASC, caprange.cran_name, capmod.cmod_name 
) x
WHERE x.MPG_VALUE IS NOT NULL;

注意,外部过滤的x.MPG_VALUE是标量查询。

编辑:您可以尝试其他方法,如,内部连接。

代码语言:javascript
复制
SELECT *, (SELECT PR_Basic + PR_VAT + PR_Delivery FROM nvdprices 
WHERE PR_Id = capder.cder_ID ORDER BY PR_EffectiveTo ASC LIMIT 1) as P11D,
MPG_VALUE.TECH_Id
from capmod
JOIN capder ON capder.cder_modcode = capmod.cmod_code 
JOIN caprange ON capder.cder_rancode = caprange.cran_code 
JOIN capman ON caprange.cran_mantextcode = capman.cman_code 
JOIN nvdmodelyear ON capder.cder_ID = MY_Id 
AND nvdmodelyear.MY_EffectiveTo = '0000-00-00 00:00:00' 
JOIN nvdtechnical ON nvdtechnical.TECH_Id = capder.cder_ID
JOIN nvddictionarytechnical ON nvddictionarytechnical.DT_TechCode = nvdtechnical.TECH_TechCode
JOIN nvddictionarycategory ON nvddictionarycategory.DC_CatCode = nvddictionarytechnical.DT_CatCode
AND nvddictionarycategory.DC_CatCode=4 
AND nvddictionarytechnical.DT_TechCode = 67
AND nvdtechnical.TECH_Value_Float >= '255' 
JOIN capfueltype ON capfueltype.cft_code = capder.cder_fueltype 
JOIN nvdbodystyle ON capmod.cmod_bodystyle = nvdbodystyle.bs_code 
INNER JOIN 
(
    SELECT TECH_Value_Float,TECH_Id
    FROM nvdtechnical 
    WHERE TECH_TechCode = '11' 
    AND TECH_Value_Float > 30
) MPG_VALUE
ON MPG_VALUE.TECH_Id = capder.cder_ID
WHERE caprange.cran_mantextcode='140' 
AND caprange.cran_code='522' 
AND capder.cder_fueltype='P' 
AND capder.cder_transmission='A' 
AND nvdbodystyle.bs_code='3' 
AND (cmod_discontinued=0 OR cmod_discontinued=2015) 
AND capman.cman_code IN ('1','140','164') 
AND caprange.cran_code IN ('924','126','147','955','965','661') 
ORDER BY P11D, capman.cman_name ASC, caprange.cran_name, capmod.cmod_name;
票数 1
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/29325608

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