Add addBottom function

Signed-off-by: David Arendsen <darendsen@gamepoint.com>

src/Builder/Universe.php

@@ -4,6 +4,7 @@ namespace Arendsen\FluxQueryBuilder\Builder;
 
 use Arendsen\FluxQueryBuilder\Builder\QueryBuilderInterface;
 use Arendsen\FluxQueryBuilder\Functions\AggregateWindow;
+use Arendsen\FluxQueryBuilder\Functions\Bottom;
 use Arendsen\FluxQueryBuilder\Functions\Count;
 use Arendsen\FluxQueryBuilder\Functions\Duplicate;
 use Arendsen\FluxQueryBuilder\Functions\First;
@@ -30,6 +31,12 @@ trait Universe
         return $this;
     }
 
+    public function addBottom(int $n, array $columns = []): QueryBuilderInterface
+    {
+        $this->addToQuery(new Bottom($n, $columns));
+        return $this;
+    }
+
     public function addCount(?string $column = null): QueryBuilderInterface
     {
         $this->addToQuery(

src/Functions/Bottom.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace Arendsen\FluxQueryBuilder\Functions;
+
+use Arendsen\FluxQueryBuilder\Type\ArrayType;
+
+class Bottom extends Base
+{
+    /**
+     * @var int $n
+     */
+    private $n;
+
+    /**
+     * @var array $columns
+     */
+    private $columns;
+
+    public function __construct($n, array $columns = [])
+    {
+        $this->n = $n;
+        $this->columns = $columns;
+    }
+
+    public function __toString()
+    {
+        $input = new ArrayType(array_filter([
+            'n' => $this->n,
+            'columns' => $this->columns ?: null,
+        ]));
+        return '|> bottom(' . $input . ') ';
+    }
+}