对于laravel 5.5.X

如果希望接收应用程序执行的每个SQL查询，可以使用listen方法。此方法对于记录查询或调试非常有用。您可以在服务提供商中注册查询侦听器：

<?php

namespace App\Providers;

use Illuminate\Support\Facades\DB;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        DB::listen(function ($query) {
            // $query->sql
            // $query->bindings
            // $query->time
        });
    }

    /**
     * Register the service provider.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}

来源

最简单的方法是故意犯错误。例如，我想查看以下关系的完整SQL查询：

public function jobs()
{
    return $this->belongsToMany(Job::class, 'eqtype_jobs')
        ->withPivot(['created_at','updated_at','id'])
        ->orderBy('pivot_created_at','desc');
}

我只是想创建一个找不到的列，这里我选择了created_at，并通过添加尾随s将其更改为created_ats：

public function jobs()
{
    return $this->belongsToMany(Job::class, 'eqtype_jobs')
        ->withPivot(['created_ats','updated_at','id'])
        ->orderBy('pivot_created_at','desc');
}

因此，调试器将返回以下错误：

（4/4）ErrorException SQLSTATE[42S22]：未找到列：1054未知“字段列表”中的列“eqtype_jobs.created_ats”（SQL:selectjobs.*，eqtype_jobs.set_id作为pivot_set_id，eqtype_jobs.job_id作为pivot_job_id，eqtype_jobs.created_ats作为pivot_created_ats，eqtype_jobs.updated_at作为pivot_updated_at，eqtype_jobs.id作为内部作业的pivot_id在jobs.id上加入eqtype_jobs.job_id，其中eqtype_jobs.set_id=56在desc limit 20时按pivot_created排序偏移量0）（视图：/home/ssad/www/factory/resources/views/set/show.blade.php）

上面的错误消息返回带有错误的完整SQL查询

SQL: select  jobs.*, eqtype_jobs.set_id as pivot_set_id,  eqtype_jobs.job_id as pivot_job_id, eqtype_jobs.created_ats as pivot_created_ats, eqtype_jobs.updated_at as  pivot_updated_at, eqtype_jobs.id as pivot_id from jobs inner join eqtype_jobs on jobs.id = eqtype_jobs.job_id where  eqtype_jobs.set_id = 56 order by pivot_created_at desc limit 20 offset 0

现在，只需从created_at中删除多余的s，并在任何SQL编辑器（如phpMyAdmin SQL编辑器）中测试该SQL！

###通知：该溶液已经用Laravel 5.4进行了测试。

如果你使用laravel 5.1和MySQL，你可以使用我制作的这个函数：

/*
 *  returns SQL with values in it
 */
function getSql($model)
{
    $replace = function ($sql, $bindings)
    {
        $needle = '?';
        foreach ($bindings as $replace){
            $pos = strpos($sql, $needle);
            if ($pos !== false) {
                if (gettype($replace) === "string") {
                     $replace = ' "'.addslashes($replace).'" ';
                }
                $sql = substr_replace($sql, $replace, $pos, strlen($needle));
            }
        }
        return $sql;
    };
    $sql = $replace($model->toSql(), $model->getBindings());
    
    return $sql;
}

作为输入参数，可以使用以下任一项

照明\数据库\口才\生成器照亮\数据库\口才\关系\ HasMany照明\数据库\查询\生成器

我创建了一些简单的函数来从一些查询中获取SQL和绑定。

/**
 * getSql
 *
 * Usage:
 * getSql( DB::table("users") )
 * 
 * Get the current SQL and bindings
 * 
 * @param  mixed  $query  Relation / Eloquent Builder / Query Builder
 * @return array          Array with sql and bindings or else false
 */
function getSql($query)
{
    if( $query instanceof Illuminate\Database\Eloquent\Relations\Relation )
    {
        $query = $query->getBaseQuery();
    }

    if( $query instanceof Illuminate\Database\Eloquent\Builder )
    {
        $query = $query->getQuery();
    }

    if( $query instanceof Illuminate\Database\Query\Builder )
    {
        return [ 'query' => $query->toSql(), 'bindings' => $query->getBindings() ];
    }

    return false;
}

/**
 * logQuery
 *
 * Get the SQL from a query in a closure
 *
 * Usage:
 * logQueries(function() {
 *     return User::first()->applications;
 * });
 * 
 * @param  closure $callback              function to call some queries in
 * @return Illuminate\Support\Collection  Collection of queries
 */
function logQueries(closure $callback) 
{
    // check if query logging is enabled
    $logging = DB::logging();

    // Get number of queries
    $numberOfQueries = count(DB::getQueryLog());

    // if logging not enabled, temporarily enable it
    if( !$logging ) DB::enableQueryLog();

    $query = $callback();

    $lastQuery = getSql($query);

    // Get querylog
    $queries = new Illuminate\Support\Collection( DB::getQueryLog() );

    // calculate the number of queries done in callback
    $queryCount = $queries->count() - $numberOfQueries;

    // Get last queries
    $lastQueries = $queries->take(-$queryCount);

    // disable query logging
    if( !$logging ) DB::disableQueryLog();

    // if callback returns a builder object, return the sql and bindings of it
    if( $lastQuery )
    {
        $lastQueries->push($lastQuery);
    }

    return $lastQueries;
}

用法：

getSql( DB::table('users') );
// returns 
// [
//     "sql" => "select * from `users`",
//     "bindings" => [],
// ]

getSql( $project->rooms() );
// returns
// [
//     "sql" => "select * from `rooms` where `rooms`.`project_id` = ? and `rooms`.`project_id` is not null",
//     "bindings" => [ 7 ],
// ]

将此代码添加到AppServiceProvider并获取日志文件

         \DB::listen(function ($query) {
             \Log::info(
                 $query->sql,
                 $query->bindings,
                 $query->time
             );
         });

DB:：QueryLog（）仅在使用$builder->get（）执行查询后才起作用。

如果要在执行查询之前或不执行查询时获取原始查询，可以使用$builder->toSql（）方法。

获取原始SQL并替换“？”的示例具有实际绑定值：

$query = str_replace(array('?'), array('\'%s\''), $builder->toSql());
$query = vsprintf($query, $builder->getBindings());
dump($query);

$result = $builder->get();

或者，您可以故意触发错误，例如，使用不存在的表或列。然后，您可以在异常消息中看到生成的查询。