diff --git a/tests/cases/standalone/common/promql/string_identifier.result b/tests/cases/standalone/common/promql/string_identifier.result
new file mode 100644
index 0000000000..77414c6810
--- /dev/null
+++ b/tests/cases/standalone/common/promql/string_identifier.result
@@ -0,0 +1,72 @@
+CREATE TABLE promql_string_identifier (
+  ts timestamp(3) time index,
+  "service.name" STRING,
+  host STRING,
+  val BIGINT,
+  PRIMARY KEY("service.name", host),
+);
+
+Affected Rows: 0
+
+INSERT INTO TABLE promql_string_identifier VALUES
+    (0, 'api-server', 'h1', 1),
+    (5000, 'db', 'host2', 2);
+
+Affected Rows: 2
+
+-- string identifier for label names with dots
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (0, 10, '5s') promql_string_identifier{"service.name"="api-server"};
+
++---------------------+--------------+------+-----+
+| ts                  | service.name | host | val |
++---------------------+--------------+------+-----+
+| 1970-01-01T00:00:00 | api-server   | h1   | 1   |
+| 1970-01-01T00:00:05 | api-server   | h1   | 1   |
+| 1970-01-01T00:00:10 | api-server   | h1   | 1   |
++---------------------+--------------+------+-----+
+
+-- string identifier for metric names in label matchers
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (0, 10, '5s') {"promql_string_identifier"};
+
++---------------------+--------------+-------+-----+
+| ts                  | service.name | host  | val |
++---------------------+--------------+-------+-----+
+| 1970-01-01T00:00:00 | api-server   | h1    | 1   |
+| 1970-01-01T00:00:05 | api-server   | h1    | 1   |
+| 1970-01-01T00:00:05 | db           | host2 | 2   |
+| 1970-01-01T00:00:10 | api-server   | h1    | 1   |
+| 1970-01-01T00:00:10 | db           | host2 | 2   |
++---------------------+--------------+-------+-----+
+
+-- string identifier in grouping labels
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (0, 10, '5s') sum by ("service.name") (promql_string_identifier);
+
++--------------+---------------------+-----------------------------------+
+| service.name | ts                  | sum(promql_string_identifier.val) |
++--------------+---------------------+-----------------------------------+
+| api-server   | 1970-01-01T00:00:00 | 1                                 |
+| api-server   | 1970-01-01T00:00:05 | 1                                 |
+| api-server   | 1970-01-01T00:00:10 | 1                                 |
+| db           | 1970-01-01T00:00:05 | 2                                 |
+| db           | 1970-01-01T00:00:10 | 2                                 |
++--------------+---------------------+-----------------------------------+
+
+-- escaped hex in label matcher value
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (0, 10, '5s') promql_string_identifier{host="\x68\x31"};
+
++---------------------+--------------+------+-----+
+| ts                  | service.name | host | val |
++---------------------+--------------+------+-----+
+| 1970-01-01T00:00:00 | api-server   | h1   | 1   |
+| 1970-01-01T00:00:05 | api-server   | h1   | 1   |
+| 1970-01-01T00:00:10 | api-server   | h1   | 1   |
++---------------------+--------------+------+-----+
+
+DROP TABLE promql_string_identifier;
+
+Affected Rows: 0
+
diff --git a/tests/cases/standalone/common/promql/string_identifier.sql b/tests/cases/standalone/common/promql/string_identifier.sql
new file mode 100644
index 0000000000..1e83ec1cd6
--- /dev/null
+++ b/tests/cases/standalone/common/promql/string_identifier.sql
@@ -0,0 +1,29 @@
+CREATE TABLE promql_string_identifier (
+  ts timestamp(3) time index,
+  "service.name" STRING,
+  host STRING,
+  val BIGINT,
+  PRIMARY KEY("service.name", host),
+);
+
+INSERT INTO TABLE promql_string_identifier VALUES
+    (0, 'api-server', 'h1', 1),
+    (5000, 'db', 'host2', 2);
+
+-- string identifier for label names with dots
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (0, 10, '5s') promql_string_identifier{"service.name"="api-server"};
+
+-- string identifier for metric names in label matchers
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (0, 10, '5s') {"promql_string_identifier"};
+
+-- string identifier in grouping labels
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (0, 10, '5s') sum by ("service.name") (promql_string_identifier);
+
+-- escaped hex in label matcher value
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (0, 10, '5s') promql_string_identifier{host="\x68\x31"};
+
+DROP TABLE promql_string_identifier;