Question

我正在开发一个花坛种植系统，并编写了一个查询8个表格的SQL语句，以便返回合适的植物列表。

表格结构： http://pastebin.com/0DUYQis1 [从phpmyadmin输出]

示例数据： http://gyazo.com/13dad0b3370b5053dbcad2a32013a54a / http://gyazo.com/1bd313adb3e8ccd01354c979e69fd059

SQL声明：

SELECT Plant.Plant_ID, Plant.Plant_Quantity, Plant.Plant_Price, Plant.Plant_Description, Plant.Plant_Latin_Name, Plant.Plant_Common_Name, Plant.Plant_Height, Plant.Plant_Spread, Plant.Plant_Type, Plant.Plant_Family, Plant.Plant_Picture, Plant_Aspect.Plant_Aspect, Plant_Flower_Colour.Plant_Flower_Colour, Plant_Flower_Colour.Plant_Season, Plant_Foliage_Colour.Plant_Foliage_Colour, Plant_Foliage_Colour.Plant_Season, Plant_Moisture.Plant_Moisture, Plant_Soil_PH.Plant_Soil_PH, Plant_Soil_Type.Plant_Soil_Type, Plant_Sun_Type.Plant_Sun_Type 

FROM Plant 

INNER JOIN Plant_Aspect ON Plant.Plant_ID = Plant_Aspect.Plant_ID 
INNER JOIN Plant_Flower_Colour ON Plant.Plant_ID = Plant_Flower_Colour.Plant_ID 
INNER JOIN Plant_Foliage_Colour ON Plant.Plant_ID = Plant_Foliage_Colour.Plant_ID 
INNER JOIN Plant_Moisture ON Plant.Plant_ID = Plant_Moisture.Plant_ID
INNER JOIN Plant_Soil_PH ON Plant.Plant_ID = Plant_Soil_PH.Plant_ID 
INNER JOIN Plant_Soil_Type ON Plant.Plant_ID = Plant_Soil_Type.Plant_ID 
INNER JOIN Plant_Sun_Type ON Plant.Plant_ID = Plant_Sun_Type.Plant_ID 

WHERE Plant_Aspect.Plant_Aspect = 'East-facing'
OR Plant_Aspect.Plant_Aspect = 'Any'
AND Plant_Soil_Type.Plant_Soil_Type = 'Sand' 
OR Plant_Soil_Type.Plant_Soil_Type = 'Any'
AND Plant_Moisture.Plant_Moisture = 'Well-drained' 
OR Plant_Moisture.Plant_Moisture = 'Any'
AND Plant_Soil_PH.Plant_Soil_PH = 'Acid'
OR Plant_Soil_PH.Plant_Soil_PH = 'Any'
AND Plant_Foliage_Colour.Plant_Foliage_Colour = 'Green'
AND Plant_Foliage_Colour.Plant_Season = 'Winter'
OR Plant_Foliage_Colour.Plant_Season = 'Any'
AND Plant_Flower_Colour.Plant_Flower_Colour = 'Orange'
AND Plant_Flower_Colour.Plant_Season = 'Winter'
OR Plant_Flower_Colour.Plant_Season = 'Any'

GROUP BY Plant_ID;

我希望查询只返回那些记录符合搜索条件的工厂，即。只有那些可以在“冬季”或“任何”季节种植的植物，而是它不应该返回的植物。

例如：http://gyazo.com/d2ca989fc6def79854a1d9b11e4bc310 - Plant_ID: 1只包含Plant_Flower_Colour表中的一条记录 - 春天的深蓝色。为什么这条记录已被退回？这就好像忽略了尾随的AND和OR。

非常感谢任何帮助！

Answer 1

我认为至少你需要在OR标准周围加上括号：

...
WHERE (Plant_Aspect.Plant_Aspect = 'East-facing'
OR Plant_Aspect.Plant_Aspect = 'Any')
AND (Plant_Soil_Type.Plant_Soil_Type = 'Sand' 
OR Plant_Soil_Type.Plant_Soil_Type = 'Any')
...

Answer 2

您需要使用括号将您的标准分组。

WHERE 
(Plant_Aspect.Plant_Aspect = 'East-facing'
OR Plant_Aspect.Plant_Aspect = 'Any')
AND (Plant_Soil_Type.Plant_Soil_Type = 'Sand' 
OR Plant_Soil_Type.Plant_Soil_Type = 'Any')...

Answer 3

和/或将使用IN（）子句的替代形式，它易于阅读，易于编辑且不易发生事故。

WHERE Plant_Aspect.Plant_Aspect IN( 'East-facing' , 'Any' )
AND Plant_Soil_Type.Plant_Soil_Type IN( 'Sand' , 'Any' )
AND Plant_Moisture.Plant_Moisture IN( 'Well-drained' , 'Any' )
AND Plant_Soil_PH.Plant_Soil_PH IN( 'Acid' , 'Any' )
AND Plant_Foliage_Colour.Plant_Foliage_Colour IN( 'Green' )
AND Plant_Foliage_Colour.Plant_Season IN( 'Winter' , 'Any' )
AND Plant_Flower_Colour.Plant_Flower_Colour IN( 'Orange' )
AND Plant_Flower_Colour.Plant_Season IN( 'Winter' , 'Any' )

Answer 4

WHERE子句中的分组是错误的 - 对普通读者来说是不明确的。 AND比OR更紧密，因此您需要使用括号使DBMS明确表达您的意图：

WHERE (Plant_Aspect.Plant_Aspect = 'East-facing'
   OR  Plant_Aspect.Plant_Aspect = 'Any')
  AND (Plant_Soil_Type.Plant_Soil_Type = 'Sand' 
   OR  Plant_Soil_Type.Plant_Soil_Type = 'Any')
  AND (Plant_Moisture.Plant_Moisture = 'Well-drained' 
   OR  Plant_Moisture.Plant_Moisture = 'Any')
  AND (Plant_Soil_PH.Plant_Soil_PH = 'Acid'
   OR  Plant_Soil_PH.Plant_Soil_PH = 'Any')
  AND  Plant_Foliage_Colour.Plant_Foliage_Colour = 'Green'
  AND (Plant_Foliage_Colour.Plant_Season = 'Winter'
   OR  Plant_Foliage_Colour.Plant_Season = 'Any')
  AND  Plant_Flower_Colour.Plant_Flower_Colour = 'Orange'
  AND (Plant_Flower_Colour.Plant_Season = 'Winter'
   OR  Plant_Flower_Colour.Plant_Season = 'Any')

你所写的内容被视为你曾写过：

WHERE Plant_Aspect.Plant_Aspect = 'East-facing' OR (Plant_Aspect.Plant_Aspect = 'Any' AND Plant_Soil_Type.Plant_Soil_Type = 'Sand') OR (Plant_Soil_Type.Plant_Soil_Type = 'Any' AND Plant_Moisture.Plant_Moisture = 'Well-drained') OR (Plant_Moisture.Plant_Moisture = 'Any' AND Plant_Soil_PH.Plant_Soil_PH = 'Acid') OR (Plant_Soil_PH.Plant_Soil_PH = 'Any' AND Plant_Foliage_Colour.Plant_Foliage_Colour = 'Green' AND Plant_Foliage_Colour.Plant_Season = 'Winter') OR (Plant_Foliage_Colour.Plant_Season = 'Any' AND Plant_Flower_Colour.Plant_Flower_Colour = 'Orange' AND Plant_Flower_Colour.Plant_Season = 'Winter') OR Plant_Flower_Colour.Plant_Season = 'Any'

Answer 5

尝试在OR比较周围放置括号。

WHERE (Plant_Aspect.Plant_Aspect = 'East-facing'
OR Plant_Aspect.Plant_Aspect = 'Any')
AND (Plant_Soil_Type.Plant_Soil_Type = 'Sand' 
OR Plant_Soil_Type.Plant_Soil_Type = 'Any')
AND (Plant_Moisture.Plant_Moisture = 'Well-drained' 
OR Plant_Moisture.Plant_Moisture = 'Any')
AND (Plant_Soil_PH.Plant_Soil_PH = 'Acid'
OR Plant_Soil_PH.Plant_Soil_PH = 'Any')
AND Plant_Foliage_Colour.Plant_Foliage_Colour = 'Green'
AND (Plant_Foliage_Colour.Plant_Season = 'Winter'
OR Plant_Foliage_Colour.Plant_Season = 'Any')
AND Plant_Flower_Colour.Plant_Flower_Colour = 'Orange'
AND (Plant_Flower_Colour.Plant_Season = 'Winter' OR Plant_Flower_Colour.Plant_Season = 'Any')

SQL查询未返回标准集

5 个答案: