Question

我看似是一组有效的SQL语句，它们在下拉方案中运行。第一个是全包式的AND，其中每个请求的选项都匹配。如果不这样做，它将转到第二个基于OR的sql调用。

有人可以向我解释或提供更好的陈述，其中第二层OR场景首先按大多数相关排序，这意味着大多数选项都匹配为第一个条目并从那里开始下降？

或者，或者，如果您有更好的方法来处理此搜索，可能只需一次调用，那就更好了。

第一个基于AND的SQL调用：

#include <iostream>
#include <vector>

class A { 
    public:
       A(int);
    private:
        int value1;
};

class B { 
    public:
       B(int);
    private:
        int value1;
};

B::B(int x) : value1(x) { std::cout << "ctor B(x)" << std::endl; }

A::A(int x) : value1(x) { std::cout << "ctor A(x) x=" << x <<std::endl; }

int A(int x) {
    std::cout << "inside A(int x) x=" << x << std::endl;
    x=x+1;
    return x;
}   


int main(){
    class A a(0);
    a = A(7);

    B b(0);

    return 0;
}

基于OR的第二层调用：

SELECT 
    l.id,l.title,l.city 
FROM listings l 
JOIN listings_facilities_xref x ON l.id = x.listing_id 
WHERE l.property_type = '1' 
    AND x.facility_id = '1' 
    AND x.facility_id = '8' 
    AND x.facility_id = '54' 
    AND x.facility_id = '11' 
    AND l.city = 'Orlando' 
    AND l.state = '16' 
GROUP BY l.id

我的表格布局如下：

SELECT l.id,l.title,l.city 
FROM listings l 
JOIN listings_facilities_xref x ON l.id = x.listing_id 
WHERE l.property_type = '1' 
AND (
    x.facility_id = '1' 
    OR x.facility_id = '8' 
    OR x.facility_id = '54' 
    OR x.facility_id = '11'
) 
AND l.city = 'Orlando' 
AND l.state = '16' 
GROUP BY l.id

示例导入数据可在以下位置找到：

商品目录：https://pastebin.com/EeuaEFrR

listings_facilities_xref：https://pastebin.com/7WeHgEaE

Answer 1

我怀疑你想要：

SELECT l.id, l.title, l.city 
FROM listings l 
JOIN listings_facilities_xref x ON l.id = x.listing_id 
WHERE l.property_type = 1 AND
      x.facility_id IN (1, 8, 54, 11) AND
      l.city = 'Orlando' AND
      l.state = 16 
GROUP BY l.id, l.title, l.city
ORDER BY COUNT(*) DESC;

我怎样才能通过最相关的方式进行这种SQL排序？

1 个答案: