diff --git a/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/UdfImpl.java b/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/UdfImpl.java
index 7ebd3faea782..237615403a10 100644
--- a/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/UdfImpl.java
+++ b/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/UdfImpl.java
@@ -70,17 +70,30 @@ public static Function create(Method method) {
   }
 
   /*
-   * Finds a method in a given class by name.
+   * Finds a method in a given class by name. In case of overloaded methods with the same name,
+   * this prioritizes the overload with the maximum number of parameters. This ensures Calcite
+   * can resolve optional/default trailing parameters correctly when binding UDF overloads.
+   *
    * @param clazz class to search method in
    * @param name name of the method to find
-   * @return the first method with matching name or null when no method found
+   * @return the matching method with the highest parameter count or null when no method found
    */
   static @Nullable Method findMethod(Class<?> clazz, String name) {
+    Method bestMethod = null;
     for (Method method : clazz.getMethods()) {
       if (method.getName().equals(name) && !method.isBridge()) {
-        return method;
+        if (bestMethod == null) {
+          bestMethod = method;
+        } else {
+          int cmp =
+              Integer.compare(
+                  method.getParameterCount(), bestMethod.getParameterCount());
+          if (cmp > 0 || (cmp == 0 && method.toString().compareTo(bestMethod.toString()) < 0)) {
+            bestMethod = method;
+          }
+        }
       }
     }
-    return null;
+    return bestMethod;
   }
 }
diff --git a/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSortRel.java b/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSortRel.java
index aaa4d66011a6..c7a0b9136bbb 100644
--- a/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSortRel.java
+++ b/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSortRel.java
@@ -40,6 +40,7 @@
 import org.apache.beam.sdk.state.ValueState;
 import org.apache.beam.sdk.transforms.DoFn;
 import org.apache.beam.sdk.transforms.Flatten;
+import org.apache.beam.sdk.transforms.GroupByKey;
 import org.apache.beam.sdk.transforms.PTransform;
 import org.apache.beam.sdk.transforms.ParDo;
 import org.apache.beam.sdk.transforms.Top;
@@ -74,15 +75,12 @@
  * <pre>{@code
  * SELECT * FROM t ORDER BY id DESC LIMIT 10;
  * SELECT * FROM t ORDER BY id DESC LIMIT 10 OFFSET 5;
- * }</pre>
- *
- * <p>but an ORDER BY without a LIMIT is NOT supported. For example, the following will throw an
- * exception:
- *
- * <pre>{@code
  * SELECT * FROM t ORDER BY id DESC;
  * }</pre>
  *
+ * <p>Note: ORDER BY without a LIMIT is supported by keying all rows to a single key and sorting
+ * them in memory. This can be memory-intensive and may fail for large datasets.
+ *
  * <h3>Constraints</h3>
  *
  * <ul>
@@ -134,12 +132,12 @@ public BeamSortRel(
     }
 
     if (fetch == null) {
-      throw new UnsupportedOperationException("ORDER BY without a LIMIT is not supported!");
+      count = -1;
+    } else {
+      RexLiteral fetchLiteral = (RexLiteral) fetch;
+      count = ((BigDecimal) fetchLiteral.getValue()).intValue();
     }
 
-    RexLiteral fetchLiteral = (RexLiteral) fetch;
-    count = ((BigDecimal) fetchLiteral.getValue()).intValue();
-
     if (offset != null) {
       RexLiteral offsetLiteral = (RexLiteral) offset;
       startIndex = ((BigDecimal) offsetLiteral.getValue()).intValue();
@@ -209,6 +207,21 @@ public PCollection<Row> expand(PCollectionList<Row> pinput) {
                   GlobalWindows.class.getSimpleName(), windowingStrategy));
         }
 
+        // When no limit is specified (count == -1), we must sort the entire dataset.
+        // To achieve this globally, we key all rows by a single dummy key, group them together
+        // using GroupByKey to ensure they are processed together, and then sort them in-memory
+        // via SortInMemoryFn. Note: This can be memory-intensive for large datasets. It should
+        // only be done as a final step when the remaining data is small
+        if (count == -1) {
+          BeamSqlRowComparator comparator =
+              new BeamSqlRowComparator(fieldIndices, orientation, nullsFirst);
+          return upstream
+              .apply("WithDummyKey", WithKeys.of("DummyKey"))
+              .apply("GroupByKey", GroupByKey.create())
+              .apply("SortInMemory", ParDo.of(new SortInMemoryFn(comparator)))
+              .setRowSchema(CalciteUtils.toSchema(getRowType()));
+        }
+
         ReversedBeamSqlRowComparator comparator =
             new ReversedBeamSqlRowComparator(fieldIndices, orientation, nullsFirst);
 
@@ -303,6 +316,31 @@ public void processElement(ProcessContext ctx) {
     }
   }
 
+  /**
+   * A {@link DoFn} that sorts all elements in-memory. Expects input grouped by a dummy key, sorts
+   * the iterable values, and outputs them.
+   */
+  private static class SortInMemoryFn extends DoFn<KV<String, Iterable<Row>>, Row> {
+    private final BeamSqlRowComparator comparator;
+
+    public SortInMemoryFn(BeamSqlRowComparator comparator) {
+      this.comparator = comparator;
+    }
+
+    @ProcessElement
+    public void processElement(ProcessContext ctx) {
+      Iterable<Row> input = ctx.element().getValue();
+      List<Row> list = new ArrayList<>();
+      for (Row r : input) {
+        list.add(r);
+      }
+      list.sort(comparator);
+      for (Row r : list) {
+        ctx.output(r);
+      }
+    }
+  }
+
   @Override
   public Sort copy(
       RelTraitSet traitSet,
diff --git a/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/utils/CalciteUtils.java b/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/utils/CalciteUtils.java
index 3aaa91680999..d55c227e7b45 100644
--- a/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/utils/CalciteUtils.java
+++ b/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/utils/CalciteUtils.java
@@ -170,6 +170,25 @@ public static boolean isStringType(FieldType fieldType) {
           FieldType.DATETIME, SqlTypeName.TIMESTAMP,
           FieldType.STRING, SqlTypeName.VARCHAR);
 
+  private static final Map<Class<?>, SqlTypeName> JAVA_TO_SQL_TYPE_MAPPING =
+      ImmutableMap.<Class<?>, SqlTypeName>builder()
+          .put(String.class, SqlTypeName.VARCHAR)
+          .put(Integer.class, SqlTypeName.INTEGER)
+          .put(int.class, SqlTypeName.INTEGER)
+          .put(Long.class, SqlTypeName.BIGINT)
+          .put(long.class, SqlTypeName.BIGINT)
+          .put(Double.class, SqlTypeName.DOUBLE)
+          .put(double.class, SqlTypeName.DOUBLE)
+          .put(Float.class, SqlTypeName.FLOAT)
+          .put(float.class, SqlTypeName.FLOAT)
+          .put(Short.class, SqlTypeName.SMALLINT)
+          .put(short.class, SqlTypeName.SMALLINT)
+          .put(Byte.class, SqlTypeName.TINYINT)
+          .put(byte.class, SqlTypeName.TINYINT)
+          .put(Boolean.class, SqlTypeName.BOOLEAN)
+          .put(boolean.class, SqlTypeName.BOOLEAN)
+          .build();
+
   // Associating FieldType to generated RelDataType objects for Beam logical types. Used for
   // recovering the original type in output schema after full Beam FieldType->Calcite Type->Beam
   // FieldType trip
@@ -365,7 +384,9 @@ private static RelDataType toRelDataType(
    * SQL-Java type mapping, with specified Beam rules: <br>
    * 1. redirect {@link AbstractInstant} to {@link Date} so Calcite can recognize it. <br>
    * 2. For a list, the component type is needed to create a Sql array type. <br>
-   * 3. For a Map, the component type is needed to create a Sql map type.
+   * 3. For a Map, the component type is needed to create a Sql map type. <br>
+   * 4. For standard Java classes (String, Integer, etc.), map them to corresponding Calcite SQL
+   * type with appropriate nullability.
    *
    * @param type
    * @return Calcite RelDataType
@@ -396,6 +417,14 @@ public static RelDataType sqlTypeWithAutoCast(RelDataTypeFactory typeFactory, Ty
               + ". This is currently unsupported, use List instead "
               + "of Array.");
     }
+    if (type instanceof Class) {
+      Class<?> clazz = (Class<?>) type;
+      SqlTypeName sqlTypeName = JAVA_TO_SQL_TYPE_MAPPING.get(clazz);
+      if (sqlTypeName != null) {
+        return typeFactory.createTypeWithNullability(
+            typeFactory.createSqlType(sqlTypeName), !clazz.isPrimitive());
+      }
+    }
     return typeFactory.createJavaType((Class) type);
   }
 }
diff --git a/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/LazyAggregateCombineFnTest.java b/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/LazyAggregateCombineFnTest.java
index 17636c628eb8..408118ff09e9 100644
--- a/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/LazyAggregateCombineFnTest.java
+++ b/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/LazyAggregateCombineFnTest.java
@@ -34,6 +34,7 @@
 import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.type.RelDataTypeSystem;
 import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.schema.AggregateFunction;
 import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.schema.FunctionParameter;
+import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.sql.type.SqlTypeName;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.junit.Rule;
@@ -77,7 +78,9 @@ public void subclassGetUdafImpl() {
       LazyAggregateCombineFn<?, ?, ?> combiner = new LazyAggregateCombineFn<>(aggregateFn);
       AggregateFunction aggregateFunction = combiner.getUdafImpl();
       RelDataTypeFactory typeFactory = new JavaTypeFactoryImpl(RelDataTypeSystem.DEFAULT);
-      RelDataType expectedType = typeFactory.createJavaType(Long.class);
+      RelDataType expectedType =
+          typeFactory.createTypeWithNullability(
+              typeFactory.createSqlType(SqlTypeName.BIGINT), true);
 
       List<FunctionParameter> params = aggregateFunction.getParameters();
       assertThat(params, hasSize(1));
diff --git a/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/UdfImplTest.java b/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/UdfImplTest.java
new file mode 100644
index 000000000000..3746b9ac8471
--- /dev/null
+++ b/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/UdfImplTest.java
@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.extensions.sql.impl;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.lang.reflect.Method;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link UdfImpl}. */
+@RunWith(JUnit4.class)
+public class UdfImplTest {
+
+  @Test
+  public void testFindMethod_overloaded_prioritizesMaxParams() {
+    Method method = UdfImpl.findMethod(OverloadedFn.class, "eval");
+    assertNotNull(method);
+    assertEquals(3, method.getParameterTypes().length);
+  }
+
+  @Test
+  public void testFindMethod_singleMethod() {
+    Method method = UdfImpl.findMethod(SingleFn.class, "eval");
+    assertNotNull(method);
+    assertEquals(1, method.getParameterTypes().length);
+  }
+
+  public static class OverloadedFn {
+    public String eval(String a) {
+      return a;
+    }
+
+    public String eval(String a, String b) {
+      return a + b;
+    }
+
+    public String eval(String a, String b, String c) {
+      return a + b + c;
+    }
+  }
+
+  public static class SingleFn {
+    public String eval(String a) {
+      return a;
+    }
+  }
+}
diff --git a/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSortRelTest.java b/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSortRelTest.java
index dbe8be441ac6..0730f17d9c84 100644
--- a/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSortRelTest.java
+++ b/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSortRelTest.java
@@ -17,6 +17,8 @@
  */
 package org.apache.beam.sdk.extensions.sql.impl.rel;
 
+import java.util.ArrayList;
+import java.util.List;
 import org.apache.beam.sdk.extensions.sql.TestUtils;
 import org.apache.beam.sdk.extensions.sql.impl.planner.BeamRelMetadataQuery;
 import org.apache.beam.sdk.extensions.sql.impl.planner.NodeStats;
@@ -24,6 +26,7 @@
 import org.apache.beam.sdk.schemas.Schema;
 import org.apache.beam.sdk.testing.PAssert;
 import org.apache.beam.sdk.testing.TestPipeline;
+import org.apache.beam.sdk.transforms.SerializableFunction;
 import org.apache.beam.sdk.values.PCollection;
 import org.apache.beam.sdk.values.Row;
 import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rel.RelNode;
@@ -316,4 +319,44 @@ public void testNodeStatsEstimation() {
     Assert.assertEquals(10., estimate.getRowCount(), 0.01);
     Assert.assertEquals(10., estimate.getWindow(), 0.01);
   }
+
+  @Test
+  public void testOrderBy_noLimit() {
+    String sql =
+        "SELECT order_id, site_id, price "
+            + "FROM ORDER_DETAILS "
+            + "ORDER BY order_id asc, site_id desc";
+
+    PCollection<Row> rows = compilePipeline(sql, pipeline);
+    PAssert.that(rows).satisfies(new AssertSorted());
+    pipeline.run().waitUntilFinish();
+  }
+
+  private static class AssertSorted implements SerializableFunction<Iterable<Row>, Void> {
+    @Override
+    public Void apply(Iterable<Row> input) {
+      List<Row> list = new ArrayList<>();
+      for (Row r : input) {
+        list.add(r);
+      }
+      Assert.assertEquals(10, list.size());
+      for (int i = 0; i < list.size() - 1; i++) {
+        Row r1 = list.get(i);
+        Row r2 = list.get(i + 1);
+        Long id1 = r1.getInt64("order_id");
+        Long id2 = r2.getInt64("order_id");
+        int comp = id1.compareTo(id2);
+        if (comp > 0) {
+          Assert.fail("Rows not sorted by order_id asc: " + list);
+        } else if (comp == 0) {
+          Integer site1 = r1.getInt32("site_id");
+          Integer site2 = r2.getInt32("site_id");
+          if (site1 < site2) {
+            Assert.fail("Rows not sorted by site_id desc when order_id is equal: " + list);
+          }
+        }
+      }
+      return null;
+    }
+  }
 }
diff --git a/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/utils/CalciteUtilsTest.java b/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/utils/CalciteUtilsTest.java
index 481a700c0c99..2cee34350249 100644
--- a/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/utils/CalciteUtilsTest.java
+++ b/sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/utils/CalciteUtilsTest.java
@@ -198,4 +198,67 @@ public void testToRelDataTypeWithRowBackedLogicalType() {
     assertEquals(1, relDataType.getFieldCount());
     assertEquals("nested_f1", relDataType.getFieldList().get(0).getName());
   }
+
+  @Test
+  public void testSqlTypeWithAutoCast() {
+    RelDataType type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, String.class);
+    assertEquals(SqlTypeName.VARCHAR, type.getSqlTypeName());
+    assertTrue(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, Integer.class);
+    assertEquals(SqlTypeName.INTEGER, type.getSqlTypeName());
+    assertTrue(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, int.class);
+    assertEquals(SqlTypeName.INTEGER, type.getSqlTypeName());
+    assertFalse(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, Long.class);
+    assertEquals(SqlTypeName.BIGINT, type.getSqlTypeName());
+    assertTrue(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, long.class);
+    assertEquals(SqlTypeName.BIGINT, type.getSqlTypeName());
+    assertFalse(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, Double.class);
+    assertEquals(SqlTypeName.DOUBLE, type.getSqlTypeName());
+    assertTrue(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, double.class);
+    assertEquals(SqlTypeName.DOUBLE, type.getSqlTypeName());
+    assertFalse(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, Float.class);
+    assertEquals(SqlTypeName.FLOAT, type.getSqlTypeName());
+    assertTrue(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, float.class);
+    assertEquals(SqlTypeName.FLOAT, type.getSqlTypeName());
+    assertFalse(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, Short.class);
+    assertEquals(SqlTypeName.SMALLINT, type.getSqlTypeName());
+    assertTrue(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, short.class);
+    assertEquals(SqlTypeName.SMALLINT, type.getSqlTypeName());
+    assertFalse(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, Byte.class);
+    assertEquals(SqlTypeName.TINYINT, type.getSqlTypeName());
+    assertTrue(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, byte.class);
+    assertEquals(SqlTypeName.TINYINT, type.getSqlTypeName());
+    assertFalse(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, Boolean.class);
+    assertEquals(SqlTypeName.BOOLEAN, type.getSqlTypeName());
+    assertTrue(type.isNullable());
+
+    type = CalciteUtils.sqlTypeWithAutoCast(dataTypeFactory, boolean.class);
+    assertEquals(SqlTypeName.BOOLEAN, type.getSqlTypeName());
+    assertFalse(type.isNullable());
+  }
 }