Unwrap LC column in IExecutablefunction::executeWithoutSparseColumns

src/Functions/IFunction.cpp

@@ -285,6 +285,8 @@ ColumnPtr IExecutableFunction::executeWithoutSparseColumns(const ColumnsWithType
                 ? res->cloneResized(1)->convertToFullColumnIfConst()
                 : res;
 
+            keys = keys->convertToFullColumnIfLowCardinality();
+            
             auto res_mut_dictionary = DataTypeLowCardinality::createColumnUnique(*res_low_cardinality_type->getDictionaryType());
             ColumnPtr res_indexes = res_mut_dictionary->uniqueInsertRangeFrom(*keys, 0, keys->size());
             ColumnUniquePtr res_dictionary = std::move(res_mut_dictionary);

tests/integration/test_cte_lc/test.py

@@ -0,0 +1,26 @@
+import pytest
+from helpers.cluster import ClickHouseCluster
+
+cluster = ClickHouseCluster(__file__)
+node = cluster.add_instance("node")
+
+
+@pytest.fixture(scope="module", autouse=True)
+def start_cluster():
+    try:
+        cluster.start()
+        yield cluster
+    finally:
+        cluster.shutdown()
+
+
+def test_lc_of_string(start_cluster):
+    result = node.query("WITH (  SELECT toLowCardinality('a') ) AS bar SELECT bar")
+
+    assert result == 'a\n'
+
+
+def test_lc_of_int(start_cluster):
+    result = node.query("WITH (  SELECT toLowCardinality(1) ) AS bar SELECT bar")
+
+    assert result == '1\n'