From 0c693137c42d43aae9b2d4cadbd45c55d7f17904 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=92=8B=E6=96=87=E5=81=A5?= <jwjbjg@gmail.com>
Date: Sun, 16 Oct 2022 22:54:00 +0800
Subject: [PATCH] =?UTF-8?q?=E5=A2=9E=E5=8A=A0=E6=9F=A5=E8=AF=A2=E8=A1=A8?=
 =?UTF-8?q?=E8=BE=BE=E5=BC=8F?=
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`===`和`!==`查询表达式不支持判断`null`，因为360行判断`$value`为`null`时，会更改查询表达式为`=`。
为了方便查询`null`的值，增加`null`和`not null`表达式
---
 src/Collection.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Collection.php b/src/Collection.php
index 9d84e1a..6fdab23 100644
--- a/src/Collection.php
+++ b/src/Collection.php
@@ -401,6 +401,10 @@ public function where(string $field, $operator, $value = null)
                 case 'not between':
                     [$min, $max] = is_string($value) ? explode(',', $value) : $value;
                     return is_scalar($result) && $result > $max || $result < $min;
+                case 'null':
+                    return $result === null;
+                case 'not null':
+                    return $result !== null;
                 case '==':
                 case '=':
                 default: