diff --git a/src/main/java/org/cbioportal/service/impl/ClinicalDataDensityPlotServiceImpl.java b/src/main/java/org/cbioportal/service/impl/ClinicalDataDensityPlotServiceImpl.java
index e4abf2e631c..940828bab10 100644
--- a/src/main/java/org/cbioportal/service/impl/ClinicalDataDensityPlotServiceImpl.java
+++ b/src/main/java/org/cbioportal/service/impl/ClinicalDataDensityPlotServiceImpl.java
@@ -34,7 +34,7 @@ public DensityPlotData getDensityPlotData(List<ClinicalData> sampleClinicalData,
         result.setBins(new ArrayList<>());
 
         Map<String, List<ClinicalData>> clinicalDataGroupedBySampleId = sampleClinicalData.stream().
-            collect(Collectors.groupingBy(ClinicalData::getSampleId));
+            collect(Collectors.groupingBy(c -> c.getStudyId() + "_" + c.getSampleId()));
 
         List<ClinicalData> extractedXYClinicalData = clinicalDataGroupedBySampleId.entrySet().stream()
             .filter(entry -> entry.getValue().size() == 2 &&
diff --git a/src/main/java/org/cbioportal/service/impl/ViolinPlotServiceImpl.java b/src/main/java/org/cbioportal/service/impl/ViolinPlotServiceImpl.java
index e3da1e50019..3b7527f8ca7 100644
--- a/src/main/java/org/cbioportal/service/impl/ViolinPlotServiceImpl.java
+++ b/src/main/java/org/cbioportal/service/impl/ViolinPlotServiceImpl.java
@@ -39,9 +39,11 @@ public ClinicalViolinPlotData getClinicalViolinPlotData(
         result.setRows(new ArrayList<>());
         
         // collect filtered samples into a set for quick lookup
-        Set<Integer> samplesForSampleCountsIds = 
+        Set<String> samplesForSampleCountsIds = 
             samplesForSampleCounts.stream()
-                .map(Sample::getInternalId)
+                .map(s -> s.getInternalId() == null ? 
+                    s.getCancerStudyIdentifier() + "_" + s.getStableId():  s.getInternalId().toString()
+                )
                 .collect(Collectors.toSet());
         
         // clinicalDataMap is a map sampleId->studyId->data
@@ -214,12 +216,14 @@ public ClinicalViolinPlotData getClinicalViolinPlotData(
     
     @SafeVarargs
     private static int countFilteredSamples(
-        Set<Integer> filteredSampleIds,
+        Set<String> filteredSampleIds,
         List<ClinicalData>... dataLists
     ) {
         return (int) Arrays.stream(dataLists)
             .flatMap(Collection::stream)
-            .map(ClinicalData::getInternalId)
+            .map(c -> c.getInternalId() == null ? 
+                c.getStudyId() + "_" + c.getSampleId() : c.getInternalId().toString()
+            )
             .filter(filteredSampleIds::contains)
             .count();
     }
diff --git a/src/main/java/org/cbioportal/web/columnar/StudyViewColumnStoreController.java b/src/main/java/org/cbioportal/web/columnar/StudyViewColumnStoreController.java
index d74af6613b9..c2aa05fa076 100644
--- a/src/main/java/org/cbioportal/web/columnar/StudyViewColumnStoreController.java
+++ b/src/main/java/org/cbioportal/web/columnar/StudyViewColumnStoreController.java
@@ -343,9 +343,12 @@ public ResponseEntity<ClinicalViolinPlotData> fetchClinicalDataViolinPlots(
         @Parameter(required = true, description = "Study view filter")
         @Valid @RequestBody(required = false) StudyViewFilter studyViewFilter) {
         
+        // fetch the samples by using the provided study view filter
         List<Sample> filteredSamples = studyViewColumnarService.getFilteredSamples(interceptedStudyViewFilter);
         
-        // get samples that are filtered without the numerical filter - this is violin plot data
+        // remove the numerical clinical data filter from the study view filter.
+        // this new modified filter is used to fetch sample and patient clinical data.
+        // this is required to get the complete violin plot data.
         if (interceptedStudyViewFilter.getClinicalDataFilters() != null) {
             interceptedStudyViewFilter.getClinicalDataFilters().stream()
                 .filter(f->f.getAttributeId().equals(numericalAttributeId))
@@ -362,11 +365,22 @@ public ResponseEntity<ClinicalViolinPlotData> fetchClinicalDataViolinPlots(
         List<ClinicalData> patientClinicalDataList = filterNonEmptyClinicalData(
             studyViewColumnarService.getPatientClinicalData(interceptedStudyViewFilter, attributeIds)
         );
-
-        List<ClinicalData> combinedClinicalDataList = Stream.concat(
-            sampleClinicalDataList.stream(),
-            convertPatientClinicalDataToSampleClinicalData(patientClinicalDataList, filteredSamples).stream()
-        ).toList();
+        
+        List<ClinicalData> combinedClinicalDataList;
+        if (patientClinicalDataList.isEmpty()) {
+            combinedClinicalDataList = sampleClinicalDataList;
+        } else {
+            // we previously fetched sample and patient clinical data with the modified study view filter,
+            // however filteredSamples reflects only the original unmodified study view filter.
+            // we need to fetch samples again to get the samples corresponding to this modified filter,
+            // otherwise patient to sample mapping may be incomplete. 
+            List<Sample> samplesWithoutNumericalFilter = studyViewColumnarService.getFilteredSamples(interceptedStudyViewFilter); 
+            
+            combinedClinicalDataList = Stream.concat(
+                sampleClinicalDataList.stream(),
+                convertPatientClinicalDataToSampleClinicalData(patientClinicalDataList, samplesWithoutNumericalFilter).stream()
+            ).toList();
+        }
         
         // Only mutation count can use log scale
         boolean useLogScale = logScale && numericalAttributeId.equals("MUTATION_COUNT");
diff --git a/src/main/java/org/cbioportal/web/columnar/util/ClinicalDataViolinPlotUtil.java b/src/main/java/org/cbioportal/web/columnar/util/ClinicalDataViolinPlotUtil.java
index 3041a1a498f..597845db2ef 100644
--- a/src/main/java/org/cbioportal/web/columnar/util/ClinicalDataViolinPlotUtil.java
+++ b/src/main/java/org/cbioportal/web/columnar/util/ClinicalDataViolinPlotUtil.java
@@ -18,14 +18,14 @@ public static List<ClinicalData> filterNonEmptyClinicalData(List<ClinicalData> c
     
     public static List<ClinicalData> convertPatientClinicalDataToSampleClinicalData(
         List<ClinicalData> patientClinicalDataList,
-        List<Sample> filteredSamples
+        List<Sample> samplesWithoutNumericalFilter
     ) {
         List<ClinicalData> sampleClinicalDataList = new ArrayList<>();
 
-        Map<String, Map<String, List<Sample>>> patientToSamples = filteredSamples
+        Map<String, Map<String, List<Sample>>> patientToSamples = samplesWithoutNumericalFilter
             .stream()
             .collect(Collectors.groupingBy(
-                s -> s.getCancerStudyIdentifier() + "_" + s.getPatientStableId(),
+                Sample::getPatientStableId,
                 Collectors.groupingBy(Sample::getCancerStudyIdentifier)
             ));
 
@@ -41,7 +41,7 @@ public static List<ClinicalData> convertPatientClinicalDataToSampleClinicalData(
                     newData.setPatientId(d.getPatientId());
                     newData.setStudyId(d.getStudyId());
                     newData.setAttrValue(d.getAttrValue());
-                    newData.setSampleId(s.getCancerStudyIdentifier() + "_" + s.getStableId());
+                    newData.setSampleId(s.getStableId());
 
                     sampleClinicalDataList.add(newData);
                 }
diff --git a/src/main/resources/org/cbioportal/persistence/mybatisclickhouse/StudyViewMapper.xml b/src/main/resources/org/cbioportal/persistence/mybatisclickhouse/StudyViewMapper.xml
index 7ed1c05f8d3..fd7d37b6d6f 100644
--- a/src/main/resources/org/cbioportal/persistence/mybatisclickhouse/StudyViewMapper.xml
+++ b/src/main/resources/org/cbioportal/persistence/mybatisclickhouse/StudyViewMapper.xml
@@ -91,8 +91,8 @@
 
     <select id="getSampleClinicalDataFromStudyViewFilter" resultType="org.cbioportal.model.ClinicalData">
         SELECT
-            sample_unique_id as sampleId,
-            patient_unique_id as patientId,
+            replaceOne(sample_unique_id, concat(cancer_study_identifier, '_'), '') as sampleId,
+            replaceOne(patient_unique_id, concat(cancer_study_identifier, '_'), '') as patientId,
             attribute_name as attrId,
             attribute_value as attrValue,
             cancer_study_identifier as studyId
@@ -113,7 +113,7 @@
 
     <select id="getPatientClinicalDataFromStudyViewFilter" resultType="org.cbioportal.model.ClinicalData">
         SELECT
-            patient_unique_id as patientId,
+            replaceOne(patient_unique_id, concat(cancer_study_identifier, '_'), '') as patientId,
             attribute_name as attrId,
             attribute_value as attrValue,
             cancer_study_identifier as studyId