Difference between Laravel's raw SQL functions

问题

It seems I'm not the only person struggling with the differences between Laravel's DB::raw(), DB::select(), DB::statement(), and DB::unprepared() methods. It seems as if one almost needs to try a given SQL statement with all 4 to identify which will work. Can anybody clarify how they relate to each other, and which to use for what purposes?

回答1:

I will try to clarify:

DB::raw()

It generates a raw and sanitized SQL string, to be passed to other query/statements, preventing SQL injections. Is to be used with all of the and never alone. And you should never send a not sanitized string to your query/statements.

DB::select(DB::raw('select * from whatever'));

DB::select()

Is for simple selects:

DB::select(DB::raw('select * from whatever'));

DB::statement()

I think it work with selects, but should be used for non SQL query commands:

DB::statement(DB::raw('update whatever set valid = true;'));

DB::unprepared()

All SQL commands in Laravel are prepared by default, but sometimes you need to execute a command in an unprepared mode, because some commands in some database cannot be ran in prepared mode. Here's an issue I opened about this: https://github.com/laravel/framework/issues/53

DB::unprepared(DB::raw('update whatever set valid = true;'));

来源：https://stackoverflow.com/questions/25346162/difference-between-laravels-raw-sql-functions