内部联接中多个列的多个AND

时间:2013-06-26 16:29:15

标签: php mysql inner-join

我有一个产品表,一个自定义定义表和一个值表:

产品

id   product_name         price
48   product one          32.99
87   another product      2.50
...etc

fielddefs

id   name
6    brand
9    colour
23   flavour
...etc

fieldvals

product_id   fielddef_id   value
48           6             Rowntree
48           9             Red
48           23            Strawberry
87           6             Cadburys
87           9             Yellow
87           23            Lemon
etc...

我现在尝试使用带有每个fielddef的下拉选项的过滤器进行搜索:

  

$ sql =“SELECT * FROM products INNER JOIN fieldvals ON   fieldvals.product_id = products.id WHERE product_name LIKE'%“。$ q。”%'   AND(fielddef_id ='7'AND value ='“。$ c。”')AND(fielddef_id ='8'AND   value ='“。$ b。”')AND(fielddef_id ='9'AND value ='“。$ f。”')AND   (fielddef_id ='10'AND value ='“。$ t。”')AND(fielddef_id ='5'AND   value ='“。$ h。”')AND(fielddef_id ='6'AND value ='“。$ v。”')“;

SQL的回声给了我类似的东西:

  

SELECT * FROM products INNER JOIN fieldvals ON   fieldvals.product_id = products.id WHERE product_name LIKE'%cola%'AND   (fielddef_id ='7'AND value ='Purple')AND(fielddef_id ='9'AND   value ='Apple')AND(fielddef_id ='10'AND value ='Party')AND   (fielddef_id ='5'AND value ='true')AND(fielddef_id ='6'AND   值= '真')

此代码仅适用于$ q之后的一个条件 - 即您可以包含$ q和$ c,或$ q和$ h,或$ q和$ v,并且它成功找到匹配的产品,但是多个嵌套的AND陈述似乎不起作用。

我哪里错了?

1 个答案:

答案 0 :(得分:1)

This link offers a similar question有人想从同一个“字段数据”表中查询并想要多个条件。

您遇到的问题是,对于任何单个记录,它们都不能具有给定列的MULTIPLE值,只能比较多个记录并应用您正在寻找的HAVING COUNT(*)=条件。另一个(根据我上面的链接)显示了这一点。现在,如何将这种类似的方法应用于您的问题。

SELECT 
      P.ID,
      P.Product_Name,
      P.Price
   FROM 
      products P
         INNER JOIN fieldvals FV1
            ON P.id = FV1.product_id 
            AND FV1.FieldDef_ID = '7'
            AND FV1.Value = 'value expected for 7'

         INNER JOIN fieldvals FV2
            ON P.id = FV2.product_id 
            AND FV2.FieldDef_ID = '8'
            AND FV2.Value = 'value expected for 8'

         INNER JOIN fieldvals FV3
            ON P.id = FV3.product_id 
            AND FV3.FieldDef_ID = '9'
            AND FV3.Value = 'value expected for 9'

         (continue same "join" sample above for as many
          criteria conditions you need to add... just keep
          incrementing the alias ... FV1, FV2, FV3, etc...)
   WHERE 
      P.Product_Name like '%your criteria%'