From 23a57f3b76dfd0b0b570046b2f79d0db548648df Mon Sep 17 00:00:00 2001
From: Johan Vervloet <johan.vervloet@kuleuven.be>
Date: Thu, 15 Jun 2017 21:51:04 +0200
Subject: [PATCH] CRM-20740 - Fix issue with check for custom_nn => ['IS NULL'
 => 1].

---
 Civi/API/Api3SelectQuery.php | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Civi/API/Api3SelectQuery.php b/Civi/API/Api3SelectQuery.php
index 1585b152b1..bb3f458ebc 100644
--- a/Civi/API/Api3SelectQuery.php
+++ b/Civi/API/Api3SelectQuery.php
@@ -89,7 +89,10 @@ class Api3SelectQuery extends SelectQuery {
         $column_name = $key;
       }
       elseif (($cf_id = \CRM_Core_BAO_CustomField::getKeyID($key)) != FALSE) {
-        list($table_name, $column_name) = $this->addCustomField($this->apiFieldSpec['custom_' . $cf_id], 'INNER');
+        // If we check a custom field on 'IS NULL', it should also work when there is no
+        // record in the custom value table, see CRM-20740.
+        $side = empty($value['IS NULL']) ? 'INNER': 'LEFT OUTER';
+        list($table_name, $column_name) = $this->addCustomField($this->apiFieldSpec['custom_' . $cf_id], $side);
       }
       elseif (strpos($key, '.')) {
         $fkInfo = $this->addFkField($key, 'INNER');
-- 
2.25.1