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。

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 ],
// ]

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

这是我可以向任何人建议的调试雄辩的最后一个查询或最终查询的最佳解决方案，尽管这也已经讨论过了：

// query builder
$query = DB::table('table_name')->where('id', 1);

// binding replaced
$sql = str_replace_array('?', $query->getBindings(), $query->toSql());

// for laravel 5.8^
$sql = Str::replaceArray('?', $query->getBindings(), $query->toSql());

// print
dd($sql);

要查看Laravel执行的查询，请使用Laravel查询日志

DB::enableQueryLog();

$queries = DB::getQueryLog();

您可以收听“illumination.query”事件。在查询之前，添加以下事件侦听器：

Event::listen('illuminate.query', function($query, $params, $time, $conn) 
{ 
    dd(array($query, $params, $time, $conn));
});

DB::table('users')->get();

这将打印出如下内容：

array(4) {
  [0]=>
  string(21) "select * from "users""
  [1]=>
  array(0) {
  }
  [2]=>
  string(4) "0.94"
  [3]=>
  string(6) "sqlite"
}