What is Database Query Builder in Laravel?

The Query Builder provides a fluent, database-agnostic interface for constructing and executing SQL queries without writing raw SQL. Access via the DB facade: DB::table("users")->where("active", 1)->orderBy("name")->get(). Key methods: select(), where(), orWhere(), whereIn(), whereBetween(), whereNull(), join(), leftJoin(), orderBy(), groupBy(), having(), limit(), offset(), insert(), update(), delete(), count(), max(), min(), avg(), sum(). Use DB::raw() for raw SQL expressions. The Query Builder automatically handles parameter binding to prevent SQL injection.