当我加入另一个表时，我在查询中发现错误

Question

当我将一张桌子加入另一张桌子时，我收到了这个错误。我把它作为关键字，但它不起作用它给我错误，比如找不到字段我该如何解决这个错误

代码：

Product::leftjoin('reviews','products.id','=','reviews.productID')
                           ->select(array('products.*',
                                    DB::raw('AVG(rating) as ratings_average')
                                ))
                        ->where(function($query) use ($categoriesID,$brands,$priceArray,$ratingArray)
                            {
                                $query->whereIn('categoryID',$categoriesID);
                                if(count($brands) > 0)
                                {
                                    $query->whereIn('brandID',$brands);
                                }
                                $query->whereBetween('productSellingPrice',$priceArray);
                                if(count($ratingArray) > 0)
                                {
                                    $query->whereBetween('ratings_average',$ratingArray);
                                }
                            })
                        ->groupBy('products.id')
                        ->get();

错误：

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'ratings_average' in 'where clause' (SQL: select `products`.*, AVG(rating) as ratings_average from `products` left join `reviews` on `products`.`id` = `reviews`.`productID` where (`categoryID` in (9, 11, 31) and `productSellingPrice` between 50 and 5000 and `ratings_average` between 1 and 2) group by `products`.`id`)

Answer 1

您可以找到$minRating 和maxRating，而不是评级数组。通过这两个值，您可以像这样运行查询：

$query->whereBetween('rating',[$minRating,$maxRtaing]);

Answer 2

这个问题是一个 SQL 问题，它与作用域有关。我不太熟悉 laravel 的 API，但生成的 SQL（基于您的有用错误消息）是：

select `products`.*, AVG(rating) as ratings_average 
    from `products` left join `reviews` on `products`.`id` = `reviews`.`productID`
    where (`categoryID` in (9, 11, 31) and `productSellingPrice` between 50 and 5000
        and `ratings_average` between 1 and 2) group by `products`.`id`)

问题是ratings_average 计算列属于GROUP BY 范围。引用该列的唯一方法是在 HAVING 语句中。您的 SQL 语句如下所示：

select `products`.*, AVG(`ratings`.`rating`) as ratings_average
    where `products`.`id` = `reviews`.`productId`
    group by `products`.`id`
    having (`categoryID` in (9, 11, 31) and `productSellingPrice` between 50 and 5000
        and `ratings_average` between 1 and 2)

从技术上讲，上述having语句中的前两个子句可以在您的WHERE子句中，但ratings_average命名列只能在HAVING子句中引用。 WHERE 和 HAVING 都会限制您的结果，但 HAVING 会在分组发生后进行评估。