条件查询闭包

PHP 闭包的用法：

$query->where(function ($query) use ($keywords) {

    $query->where('items'  , 'like', $keywords)

        ->orwhere('content', 'like', $keywords);

});

laravel 查询闭包

if (isset($priority)) {

                $query->where("priority", $priority);

            }

            // 把名字搜索下面几个条件放在大括号里 不能与 priority 条件 同级别 会影响

            // 如果不放 就这样。

            // select * from `trials` where (`priority` = 0 and `name` like '%肺癌%'or `diseases` like '%肺癌%') 

            // and `trials`.`deleted_at` is null order by `created_at` desc limit 100000 offset 0

            // 放了之后

            // select * from `trials` where `priority` = ? and (`name` like ? or `diseases` like ? or `code` like ?) 

            // and `trials`.`deleted_at` is null order by `created_at` desc limit 100000 offset 0

            if (!empty($name)) {

                $query->where(function ($query) use ($name) {

                    $query->where("name", 'like', "%$name%")

                    ->orwhere("name_abbr", 'like', "%$name%")

                    ->orwhere("name_abbr_out", 'like', "%$name%")

                    ->orwhere("diseases", 'like', "%$name%")

                    ->orwhere("code", 'like', "%$name%");           

                });

            }

此时,这里的sql 查询,priority 这个条件 将会与下面大段条件分开.
sql 语句如下:

select * from `trials` where `priority` = ? and (`name` like ? or `diseases` like ? or `code` like ?) and `trials`.`deleted_at` is null order by `created_at` desc limit 100000 offset 0

运行结果:

解惑试验-不闭包的sql

我们这样子写 query

if (!empty($name)) {

                $query->where("name", 'like', "%$name%")

                ->orwhere("name_abbr", 'like', "%$name%")

                ->orwhere("name_abbr_out", 'like', "%$name%")

                ->orwhere("diseases", 'like', "%$name%")

                ->orwhere("code", 'like', "%$name%");

            }

            if (isset($priority)) {

                $query->where("priority", $priority);

            }

sql语句如下:

select * from `trials` where (`priority` = 0 and `name` like '%肺癌%'or `diseases` like '%肺癌%') and `trials`.`deleted_at` is null order by `created_at` desc limit 100000 offset 0

运行结果: 就搜索到了,状态不对的一条(理应是空结果).

小结

这时候,priority 这个条件 将会与下面大段条件联合在一起. 同时享受了 orwhere.

这就影响了我们对priority条件的先决性.
所以,我们采用括号,括起来.
在.laravel中, 我们就使用闭包就好啦.

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