diff --git a/changelog.txt b/changelog.txt
index 3df9a2d7..0bb6e484 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -1,5 +1,9 @@
 This file shows the changes in this release of xPDO.
 
+Unreleased
+====================================
+- [#54] Fix updateCollection/set() when string value contains SQL operator keywords (e.g. IN, LIKE)
+
 xPDO 3.1.7 (December 4, 2025)
 ====================================
 - PHP 8.5 compatibility (#264)
diff --git a/src/xPDO/Om/mysql/xPDOQuery.php b/src/xPDO/Om/mysql/xPDOQuery.php
index 38988237..356bcd43 100644
--- a/src/xPDO/Om/mysql/xPDOQuery.php
+++ b/src/xPDO/Om/mysql/xPDOQuery.php
@@ -78,8 +78,8 @@ public function construct() {
                 foreach ($this->query['set'] as $setKey => $setVal) {
                     $value = $setVal['value'];
                     $type = $setVal['type'];
-                    if ($value !== null && in_array($type, array(\PDO::PARAM_INT, \PDO::PARAM_STR))) {
-                        $value = $this->xpdo->quote($value, $type);
+                    if ($value !== null && ($type === null || in_array($type, array(\PDO::PARAM_INT, \PDO::PARAM_STR)))) {
+                        $value = $this->xpdo->quote($value, $type === null ? \PDO::PARAM_STR : $type);
                     } elseif ($value === null) {
                         $value = 'NULL';
                     }
diff --git a/src/xPDO/Om/pgsql/xPDOQuery.php b/src/xPDO/Om/pgsql/xPDOQuery.php
index 095eeec0..80a08a05 100644
--- a/src/xPDO/Om/pgsql/xPDOQuery.php
+++ b/src/xPDO/Om/pgsql/xPDOQuery.php
@@ -69,8 +69,8 @@ public function construct() {
                 foreach ($this->query['set'] as $setKey => $setVal) {
                     $value = $setVal['value'];
                     $type = $setVal['type'];
-                    if ($value !== null && in_array($type, array(\PDO::PARAM_INT, \PDO::PARAM_STR))) {
-                        $value = $this->xpdo->quote($value, $type);
+                    if ($value !== null && ($type === null || in_array($type, array(\PDO::PARAM_INT, \PDO::PARAM_STR)))) {
+                        $value = $this->xpdo->quote($value, $type === null ? \PDO::PARAM_STR : $type);
                     } elseif ($value === null) {
                         $value = 'NULL';
                     }
diff --git a/src/xPDO/Om/sqlite/xPDOQuery.php b/src/xPDO/Om/sqlite/xPDOQuery.php
index f2364402..3e944803 100644
--- a/src/xPDO/Om/sqlite/xPDOQuery.php
+++ b/src/xPDO/Om/sqlite/xPDOQuery.php
@@ -78,8 +78,8 @@ public function construct() {
                 foreach ($this->query['set'] as $setKey => $setVal) {
                     $value = $setVal['value'];
                     $type = $setVal['type'];
-                    if ($value !== null && in_array($type, array(\PDO::PARAM_INT, \PDO::PARAM_STR))) {
-                        $value = $this->xpdo->quote($value, $type);
+                    if ($value !== null && ($type === null || in_array($type, array(\PDO::PARAM_INT, \PDO::PARAM_STR)))) {
+                        $value = $this->xpdo->quote($value, $type === null ? \PDO::PARAM_STR : $type);
                     } elseif ($value === null) {
                         $value = 'NULL';
                     }
diff --git a/src/xPDO/Om/sqlsrv/xPDOQuery.php b/src/xPDO/Om/sqlsrv/xPDOQuery.php
index d191ea95..86c725d4 100644
--- a/src/xPDO/Om/sqlsrv/xPDOQuery.php
+++ b/src/xPDO/Om/sqlsrv/xPDOQuery.php
@@ -249,8 +249,8 @@ public function construct() {
                 foreach ($this->query['set'] as $setKey => $setVal) {
                     $value = $setVal['value'];
                     $type = $setVal['type'];
-                    if ($value !== null && in_array($type, array(\PDO::PARAM_INT, \PDO::PARAM_STR))) {
-                        $value = $this->xpdo->quote($value, $type);
+                    if ($value !== null && ($type === null || in_array($type, array(\PDO::PARAM_INT, \PDO::PARAM_STR)))) {
+                        $value = $this->xpdo->quote($value, $type === null ? \PDO::PARAM_STR : $type);
                     } elseif ($value === null) {
                         $value = 'NULL';
                     }
diff --git a/src/xPDO/Om/xPDOQuery.php b/src/xPDO/Om/xPDOQuery.php
index c4e98907..59307fc3 100644
--- a/src/xPDO/Om/xPDOQuery.php
+++ b/src/xPDO/Om/xPDOQuery.php
@@ -264,7 +264,7 @@ public function set(array $values) {
                 elseif (!in_array($fieldMeta[$key]['phptype'], $this->_quotable)) {
                     $type= \PDO::PARAM_INT;
                 }
-                elseif (strpos($value, '(') === false && !$this->isConditionalClause($value)) {
+                else {
                     $type= \PDO::PARAM_STR;
                 }
                 $this->query['set'][$key]= array('value' => $value, 'type' => $type);
diff --git a/test/xPDO/Legacy/Om/xPDOObjectTest.php b/test/xPDO/Legacy/Om/xPDOObjectTest.php
index 7d336fbc..7c4779c2 100644
--- a/test/xPDO/Legacy/Om/xPDOObjectTest.php
+++ b/test/xPDO/Legacy/Om/xPDOObjectTest.php
@@ -630,20 +630,56 @@ public function testUpdateCollection($class, $set, $criteria, $expected)
     public function providerUpdateCollection()
     {
         return array(
-            array('Person', array('dob' => '2011-08-09'), array('dob:<' => '1951-01-01'), array(1, array())),
-            array('Person', array('security_level' => 5), array('security_level' => 3), array(1, array())),
-            array(
+            'no matches' => array('Person', array('dob' => '2011-08-09'), array('dob:<' => '1951-01-01'), array(1, array())),
+            'integer field' => array('Person', array('security_level' => 5), array('security_level' => 3), array(1, array())),
+            'update all records' => array(
                 'Person',
                 array('date_of_birth' => '2011-09-01'),
                 null,
                 array(2, array(array('date_of_birth' => '2011-09-01'), array('date_of_birth' => '2011-09-01')))
             ),
-            array(
+            'null value' => array(
                 'Person',
                 array('date_of_birth' => null),
                 array('security_level' => 3),
                 array(1, array(array('date_of_birth' => null)))
             ),
+            'string with IN' => array(
+                'Person',
+                array('first_name' => 'The word IN is IN this strINg'),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => 'The word IN is IN this strINg')))
+            ),
+            'string with LIKE' => array(
+                'Person',
+                array('first_name' => 'Something LIKE %test%'),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => 'Something LIKE %test%')))
+            ),
+            'string with BETWEEN' => array(
+                'Person',
+                array('first_name' => 'Value BETWEEN 1 AND 10'),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => 'Value BETWEEN 1 AND 10')))
+            ),
+            'string with equals' => array(
+                'Person',
+                array('first_name' => 'x = y'),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => 'x = y')))
+            ),
+            'empty string' => array(
+                'Person',
+                array('middle_name' => ''),
+                array('security_level' => 3),
+                array(1, array(array('middle_name' => '')))
+            ),
+            'apostrophe SQL injection' => array(
+                'Person',
+                array('first_name' => "O'Brien"),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => "O'Brien")))
+            ),
         );
     }
 
diff --git a/test/xPDO/Test/Om/xPDOObjectTest.php b/test/xPDO/Test/Om/xPDOObjectTest.php
index 2117a2f3..ebaa1b2e 100644
--- a/test/xPDO/Test/Om/xPDOObjectTest.php
+++ b/test/xPDO/Test/Om/xPDOObjectTest.php
@@ -661,20 +661,56 @@ public function testUpdateCollection($class, $set, $criteria, $expected)
     public function providerUpdateCollection()
     {
         return array(
-            array('xPDO\\Test\\Sample\\Person', array('dob' => '2011-08-09'), array('dob:<' => '1951-01-01'), array(1, array())),
-            array('xPDO\\Test\\Sample\\Person', array('security_level' => 5), array('security_level' => 3), array(1, array())),
-            array(
+            'no matches' => array('xPDO\\Test\\Sample\\Person', array('dob' => '2011-08-09'), array('dob:<' => '1951-01-01'), array(1, array())),
+            'integer field' => array('xPDO\\Test\\Sample\\Person', array('security_level' => 5), array('security_level' => 3), array(1, array())),
+            'update all records' => array(
                 'xPDO\\Test\\Sample\\Person',
                 array('date_of_birth' => '2011-09-01'),
                 null,
                 array(2, array(array('date_of_birth' => '2011-09-01'), array('date_of_birth' => '2011-09-01')))
             ),
-            array(
+            'null value' => array(
                 'xPDO\\Test\\Sample\\Person',
                 array('date_of_birth' => null),
                 array('security_level' => 3),
                 array(1, array(array('date_of_birth' => null)))
             ),
+            'string with IN' => array(
+                'xPDO\\Test\\Sample\\Person',
+                array('first_name' => 'The word IN is IN this strINg'),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => 'The word IN is IN this strINg')))
+            ),
+            'string with LIKE' => array(
+                'xPDO\\Test\\Sample\\Person',
+                array('first_name' => 'Something LIKE %test%'),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => 'Something LIKE %test%')))
+            ),
+            'string with BETWEEN' => array(
+                'xPDO\\Test\\Sample\\Person',
+                array('first_name' => 'Value BETWEEN 1 AND 10'),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => 'Value BETWEEN 1 AND 10')))
+            ),
+            'string with equals' => array(
+                'xPDO\\Test\\Sample\\Person',
+                array('first_name' => 'x = y'),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => 'x = y')))
+            ),
+            'empty string' => array(
+                'xPDO\\Test\\Sample\\Person',
+                array('middle_name' => ''),
+                array('security_level' => 3),
+                array(1, array(array('middle_name' => '')))
+            ),
+            'apostrophe SQL injection' => array(
+                'xPDO\\Test\\Sample\\Person',
+                array('first_name' => "O'Brien"),
+                array('security_level' => 3),
+                array(1, array(array('first_name' => "O'Brien")))
+            ),
         );
     }