diff --git a/engine/src/main/java/com/arcadedb/query/sql/parser/MethodCall.java b/engine/src/main/java/com/arcadedb/query/sql/parser/MethodCall.java
index 1a2d83832a..a8aadcab0b 100755
--- a/engine/src/main/java/com/arcadedb/query/sql/parser/MethodCall.java
+++ b/engine/src/main/java/com/arcadedb/query/sql/parser/MethodCall.java
@@ -97,6 +97,8 @@ private Object execute(final Object targetObjects, final CommandContext context,
         paramValues.add(expr.execute(identifiable, context));
       } else if (targetObjects instanceof Result result) {
         paramValues.add(expr.execute(result, context));
+      } else if (val == null) {
+        paramValues.add(expr.execute((Identifiable) null, context));
       } else {
         throw new CommandExecutionException("Invalid value for $current: " + val);
       }
diff --git a/engine/src/test/java/com/arcadedb/function/sql/sql/SQLFunctionsTest.java b/engine/src/test/java/com/arcadedb/function/sql/sql/SQLFunctionsTest.java
index b7f33e4923..b42e608e1d 100755
--- a/engine/src/test/java/com/arcadedb/function/sql/sql/SQLFunctionsTest.java
+++ b/engine/src/test/java/com/arcadedb/function/sql/sql/SQLFunctionsTest.java
@@ -608,6 +608,39 @@ void querySplit() {
     }
   }
 
+  @Test
+  void queryUnionAllWithLetAndStringMethods() {
+    database.getSchema().createDocumentType("NER");
+    database.getSchema().createDocumentType("THEME");
+    database.transaction(() -> {
+      database.newDocument("NER").set("identity", "Hello World").save();
+      database.newDocument("NER").set("identity", "Hello\nWorld").save();
+      database.newDocument("THEME").set("identity", "Hello World Theme").save();
+    });
+
+    final Map<String, Object> params = new HashMap<>();
+    params.put("keyWordIdentifier_0", "Hello");
+    params.put("keyWordIdentifier_1", "World");
+
+    final ResultSet result = database.query("sql",
+        "SELECT expand($c) LET "
+            + "$a = (SELECT identity, @rid as id FROM NER "
+            + "WHERE identity.replace('\\n', ' ').replace('\\t', ' ').replace('  ', ' ') ILIKE ('%' + :keyWordIdentifier_0 + '%') "
+            + "AND identity.replace('\\n', ' ').replace('\\t', ' ').replace('  ', ' ') ILIKE ('%' + :keyWordIdentifier_1 + '%')), "
+            + "$b = (SELECT identity, @rid as id FROM THEME "
+            + "WHERE identity.replace('\\n', ' ').replace('\\t', ' ').replace('  ', ' ') ILIKE ('%' + :keyWordIdentifier_0 + '%') "
+            + "AND identity.replace('\\n', ' ').replace('\\t', ' ').replace('  ', ' ') ILIKE ('%' + :keyWordIdentifier_1 + '%')), "
+            + "$c = UNIONALL($a, $b)",
+        params);
+
+    final List<Result> results = result.stream().collect(Collectors.toList());
+    assertThat(results).hasSize(3);
+    for (final Result r : results) {
+      assertThat(r.hasProperty("identity")).isTrue();
+      assertThat(r.hasProperty("id")).isTrue();
+    }
+  }
+
   @Test
   void CheckAllFunctions() {
     final DefaultSQLFunctionFactory fFactory = ((SQLQueryEngine) database.getQueryEngine("sql")).getFunctionFactory();