Store empty user_func as null (#14900)

database/migrations/2023_03_14_130653_migrate_empty_user_funcs_to_null.php

@@ -0,0 +1,25 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+
+class MigrateEmptyUserFuncsToNull extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        \App\Models\Sensor::where('user_func', '')->update(['user_func' => null]);
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+    }
+}