spa-api/laravel/documentation/database/fluent.md

# Fluent Query Builder

## Contents

- [The Basics](#the-basics)
- [Retrieving Records](#get)
- [Building Where Clauses](#where)
- [Nested Where Clauses](#nested-where)
- [Dynamic Where Clauses](#dynamic)
- [Table Joins](#joins)
- [Ordering Results](#ordering)
- [Grouping Results](#grouping)
- [Skip & Take](#limit)
- [Aggregates](#aggregates)
- [Expressions](#expressions)
- [Inserting Records](#insert)
- [Updating Records](#update)
- [Deleting Records](#delete)

## The Basics

The Fluent Query Builder is Laravel's powerful fluent interface for building SQL queries and working with your database. All queries use prepared statements and are protected against SQL injection.

You can begin a fluent query using the **table** method on the DB class. Just mention the table you wish to query:

	$query = DB::table('users');

You now have a fluent query builder for the "users" table. Using this query builder, you can retrieve, insert, update, or delete records from the table.

<a name="get"></a>
## Retrieving Records

#### Retrieving an array of records from the database:

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

> **Note:** The **get** method returns an array of objects with properties corresponding to the column on the table.

#### Retrieving a single record from the database:

	$user = DB::table('users')->first();
	
#### Retrieving a single record by its primary key:

	$user = DB::table('users')->find($id);

> **Note:** If no results are found, the **first** method will return NULL. The **get** method will return an empty array.

#### Retrieving the value of a single column from the database:

	$email = DB::table('users')->where('id', '=', 1)->only('email');

#### Only selecting certain columns from the database:

	$user = DB::table('users')->get(array('id', 'email as user_email'));

#### Retrieving an array with the values of a given column:

    $users = DB::table('users')->take(10)->lists('email', 'id');

> **Note:** Second parameter is optional

#### Selecting distinct results from the database:

	$user = DB::table('users')->distinct()->get();

<a name="where"></a>
## Building Where Clauses

### where and or\_where

There are a variety of methods to assist you in building where clauses. The most basic of these methods are the **where** and **or_where** methods. Here is how to use them:

	return DB::table('users')
		->where('id', '=', 1)
		->or_where('email', '=', 'example@gmail.com')
		->first();

Of course, you are not limited to simply checking equality. You may also use **greater-than**, **less-than**, **not-equal**, and **like**:

	return DB::table('users')
		->where('id', '>', 1)
		->or_where('name', 'LIKE', '%Taylor%')
		->first();

As you may have assumed, the **where** method will add to the query using an AND condition, while the **or_where** method will use an OR condition.

### where\_in, where\_not\_in, or\_where\_in, and or\_where\_not\_in

The suite of **where_in** methods allows you to easily construct queries that search an array of values:

	DB::table('users')->where_in('id', array(1, 2, 3))->get();

	DB::table('users')->where_not_in('id', array(1, 2, 3))->get();

	DB::table('users')
		->where('email', '=', 'example@gmail.com')
		->or_where_in('id', array(1, 2, 3))
		->get();

	DB::table('users')
		->where('email', '=', 'example@gmail.com')
		->or_where_not_in('id', array(1, 2, 3))
		->get();

### where\_null, where\_not\_null, or\_where\_null, and or\_where\_not\_null

The suite of **where_null** methods makes checking for NULL values a piece of cake:

	return DB::table('users')->where_null('updated_at')->get();

	return DB::table('users')->where_not_null('updated_at')->get();

	return DB::table('users')
		->where('email', '=', 'example@gmail.com')
		->or_where_null('updated_at')
		->get();

	return DB::table('users')
		->where('email', '=', 'example@gmail.com')
		->or_where_not_null('updated_at')
		->get();

<a name="nested-where"></a>
## Nested Where Clauses

You may discover the need to group portions of a WHERE clause within parentheses. Just pass a Closure as parameter to the **where** or **or_where** methods:

	$users = DB::table('users')
		->where('id', '=', 1)
		->or_where(function($query)
		{
			$query->where('age', '>', 25);
			$query->where('votes', '>', 100);
		})
		->get();

The example above would generate a query that looks like:

	SELECT * FROM "users" WHERE "id" = ? OR ("age" > ? AND "votes" > ?)

<a name="dynamic"></a>
## Dynamic Where Clauses

Dynamic where methods are great way to increase the readability of your code. Here are some examples:

	$user = DB::table('users')->where_email('example@gmail.com')->first();

	$user = DB::table('users')->where_email_and_password('example@gmail.com', 'secret');

	$user = DB::table('users')->where_id_or_name(1, 'Fred');


<a name="joins"></a>
## Table Joins

Need to join to another table? Try the **join** and **left\_join** methods:

	DB::table('users')
		->join('phone', 'users.id', '=', 'phone.user_id')
		->get(array('users.email', 'phone.number'));

The **table** you wish to join is passed as the first parameter. The remaining three parameters are used to construct the **ON** clause of the join.

Once you know how to use the join method, you know how to **left_join**. The method signatures are the same:

	DB::table('users')
		->left_join('phone', 'users.id', '=', 'phone.user_id')
		->get(array('users.email', 'phone.number'));

You may also specify multiple conditions for an **ON** clause by passing a Closure as the second parameter of the join:

	DB::table('users')
		->join('phone', function($join)
		{
			$join->on('users.id', '=', 'phone.user_id');
			$join->or_on('users.id', '=', 'phone.contact_id');
		})
		->get(array('users.email', 'phone.number'));

<a name="ordering"></a>
## Ordering Results

You can easily order the results of your query using the **order_by** method. Simply mention the column and direction (desc or asc) of the sort:

	return DB::table('users')->order_by('email', 'desc')->get();

Of course, you may sort on as many columns as you wish:

	return DB::table('users')
		->order_by('email', 'desc')
		->order_by('name', 'asc')
		->get();

<a name="grouping"></a>
## Grouping Results

You can easily group the results of your query using the **group_by** method:

	return DB::table(...)->group_by('email')->get();

<a name="limit"></a>
## Skip & Take

If you would like to **LIMIT** the number of results returned by your query, you can use the **take** method:

	return DB::table('users')->take(10)->get();

To set the **OFFSET** of your query, use the **skip** method:

	return DB::table('users')->skip(10)->get();

<a name="aggregates"></a>
## Aggregates

Need to get a **MIN**, **MAX**, **AVG**, **SUM**, or **COUNT** value? Just pass the column to the query:

	$min = DB::table('users')->min('age');

	$max = DB::table('users')->max('weight');

	$avg = DB::table('users')->avg('salary');

	$sum = DB::table('users')->sum('votes');

	$count = DB::table('users')->count();

Of course, you may wish to limit the query using a WHERE clause first:

	$count = DB::table('users')->where('id', '>', 10)->count();

<a name="expressions"></a>
## Expressions

Sometimes you may need to set the value of a column to a SQL function such as **NOW()**. Usually a reference to now() would automatically be quoted and escaped. To prevent this use the **raw** method on the **DB** class. Here's what it looks like:

	DB::table('users')->update(array('updated_at' => DB::raw('NOW()')));

The **raw** method tells the query to inject the contents of the expression into the query as a string rather than a bound parameter. For example, you can also use expressions to increment column values:

	DB::table('users')->update(array('votes' => DB::raw('votes + 1')));

Of course, convenient methods are provided for **increment** and **decrement**:

	DB::table('users')->increment('votes');

	DB::table('users')->decrement('votes');

<a name="insert"></a>
## Inserting Records

The insert method expects an array of values to insert. The insert method will return true or false, indicating whether the query was successful:

	DB::table('users')->insert(array('email' => 'example@gmail.com'));

Inserting a record that has an auto-incrementing ID? You can use the **insert\_get\_id** method to insert a record and retrieve the ID:

	$id = DB::table('users')->insert_get_id(array('email' => 'example@gmail.com'));

> **Note:** The **insert\_get\_id** method expects the name of the auto-incrementing column to be "id".

<a name="update"></a>
## Updating Records

To update records simply pass an array of values to the **update** method:

	$affected = DB::table('users')->update(array('email' => 'new_email@gmail.com'));

Of course, when you only want to update a few records, you should add a WHERE clause before calling the update method:

	$affected = DB::table('users')
		->where('id', '=', 1)
		->update(array('email' => 'new_email@gmail.com'));

<a name="delete"></a>
## Deleting Records

When you want to delete records from your database, simply call the **delete** method:

	$affected = DB::table('users')->where('id', '=', 1)->delete();

Want to quickly delete a record by its ID? No problem. Just pass the ID into the delete method:

	$affected = DB::table('users')->delete(1);