diff --git a/datafusion/physical-plan/src/stream.rs b/datafusion/physical-plan/src/stream.rs
index 338ac7d048a33..6ffe7732da5ca 100644
--- a/datafusion/physical-plan/src/stream.rs
+++ b/datafusion/physical-plan/src/stream.rs
@@ -26,6 +26,7 @@ use super::metrics::BaselineMetrics;
 use super::{ExecutionPlan, RecordBatchStream, SendableRecordBatchStream};
 use crate::displayable;
 
+use arrow::array::RecordBatchOptions;
 use arrow::{datatypes::SchemaRef, record_batch::RecordBatch};
 use datafusion_common::{exec_err, Result};
 use datafusion_common_runtime::JoinSet;
@@ -362,6 +363,8 @@ pin_project! {
 
         #[pin]
         stream: S,
+
+        transform_schema: bool,
     }
 }
 
@@ -389,7 +392,19 @@ impl<S> RecordBatchStreamAdapter<S> {
     /// // ...
     /// ```
     pub fn new(schema: SchemaRef, stream: S) -> Self {
-        Self { schema, stream }
+        Self {
+            schema,
+            stream,
+            transform_schema: false,
+        }
+    }
+
+    pub fn new_with_transform_schema(schema: SchemaRef, stream: S) -> Self {
+        Self {
+            schema,
+            stream,
+            transform_schema: true,
+        }
     }
 }
 
@@ -408,7 +423,25 @@ where
     type Item = Result<RecordBatch>;
 
     fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        self.project().stream.poll_next(cx)
+        let this = self.project();
+        let transform_schema = *this.transform_schema;
+        let schema = Arc::clone(this.schema);
+        let ret = this.stream.poll_next(cx);
+        if transform_schema {
+            if let Poll::Ready(Some(Ok(batch))) = ret {
+                let options =
+                    RecordBatchOptions::default().with_row_count(Some(batch.num_rows()));
+                return Poll::Ready(Some(
+                    RecordBatch::try_new_with_options(
+                        schema,
+                        batch.columns().to_vec(),
+                        &options,
+                    )
+                    .map_err(|e| datafusion_common::DataFusionError::ArrowError(e, None)),
+                ));
+            }
+        }
+        ret
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {
diff --git a/datafusion/physical-plan/src/union.rs b/datafusion/physical-plan/src/union.rs
index 2b666093f29e0..825fd7fffb44f 100644
--- a/datafusion/physical-plan/src/union.rs
+++ b/datafusion/physical-plan/src/union.rs
@@ -37,7 +37,7 @@ use crate::execution_plan::{
 };
 use crate::metrics::BaselineMetrics;
 use crate::projection::{make_with_child, ProjectionExec};
-use crate::stream::ObservedStream;
+use crate::stream::{ObservedStream, RecordBatchStreamAdapter};
 
 use arrow::datatypes::{Field, Schema, SchemaRef};
 use arrow::record_batch::RecordBatch;
@@ -236,8 +236,15 @@ impl ExecutionPlan for UnionExec {
         for input in self.inputs.iter() {
             // Calculate whether partition belongs to the current partition
             if partition < input.output_partitioning().partition_count() {
-                let stream = input.execute(partition, context)?;
+                let mut stream = input.execute(partition, context)?;
                 debug!("Found a Union partition to execute");
+                if self.schema() != stream.schema() {
+                    stream =
+                        Box::pin(RecordBatchStreamAdapter::new_with_transform_schema(
+                            self.schema(),
+                            stream,
+                        ));
+                }
                 return Ok(Box::pin(ObservedStream::new(
                     stream,
                     baseline_metrics,
diff --git a/datafusion/sqllogictest/test_files/union_by_name.slt b/datafusion/sqllogictest/test_files/union_by_name.slt
index 9572e6efc3e67..52b6fcf9f72ce 100644
--- a/datafusion/sqllogictest/test_files/union_by_name.slt
+++ b/datafusion/sqllogictest/test_files/union_by_name.slt
@@ -335,89 +335,8 @@ a b c
 a b c
 
 
-# FIXME: The following should pass without error, but currently it is failing
-# due to differing record batch schemas when the SLT runner collects results.
-# This is due to the following issue: https://github.com/apache/datafusion/issues/15394#issue-2943811768
-#
-# More context can be found here: https://github.com/apache/datafusion/pull/15242#issuecomment-2746563234
-query error
+query TTTT rowsort
 select x, y, z from t3 union all by name select z, y, x, 'd' as zz from t3;
 ----
-DataFusion error: Internal error: Schema mismatch. Previously had
-Schema {
-    fields: [
-        Field {
-            name: "x",
-            data_type: Utf8,
-            nullable: true,
-            dict_id: 0,
-            dict_is_ordered: false,
-            metadata: {},
-        },
-        Field {
-            name: "y",
-            data_type: Utf8,
-            nullable: true,
-            dict_id: 0,
-            dict_is_ordered: false,
-            metadata: {},
-        },
-        Field {
-            name: "z",
-            data_type: Utf8,
-            nullable: true,
-            dict_id: 0,
-            dict_is_ordered: false,
-            metadata: {},
-        },
-        Field {
-            name: "zz",
-            data_type: Utf8,
-            nullable: false,
-            dict_id: 0,
-            dict_is_ordered: false,
-            metadata: {},
-        },
-    ],
-    metadata: {},
-}
-
-Got:
-Schema {
-    fields: [
-        Field {
-            name: "x",
-            data_type: Utf8,
-            nullable: true,
-            dict_id: 0,
-            dict_is_ordered: false,
-            metadata: {},
-        },
-        Field {
-            name: "y",
-            data_type: Utf8,
-            nullable: true,
-            dict_id: 0,
-            dict_is_ordered: false,
-            metadata: {},
-        },
-        Field {
-            name: "z",
-            data_type: Utf8,
-            nullable: true,
-            dict_id: 0,
-            dict_is_ordered: false,
-            metadata: {},
-        },
-        Field {
-            name: "zz",
-            data_type: Utf8,
-            nullable: true,
-            dict_id: 0,
-            dict_is_ordered: false,
-            metadata: {},
-        },
-    ],
-    metadata: {},
-}.
-This was likely caused by a bug in DataFusion's code and we would welcome that you file an bug report in our issue tracker
+a b c NULL
+a b c d