diff --git a/core/wren/src/wren/connector/clickhouse.py b/core/wren/src/wren/connector/clickhouse.py
index ad872dc83a..1e8310a7e6 100644
--- a/core/wren/src/wren/connector/clickhouse.py
+++ b/core/wren/src/wren/connector/clickhouse.py
@@ -13,7 +13,7 @@
 import re
 from decimal import Decimal as PyDecimal
 from typing import Any
-from urllib.parse import parse_qsl, unquote_plus, urlparse
+from urllib.parse import parse_qsl, unquote, urlparse
 
 import pyarrow as pa
 import sqlglot
@@ -258,9 +258,12 @@ def _build_clickhouse_client_kwargs(connection_info: Any) -> dict:
         if statement_timeout is not None:
             settings["max_execution_time"] = int(statement_timeout)
 
-        # urlparse leaves percent-encoded characters in userinfo, so decode
-        # them before clickhouse-connect sees the credentials. Matches the
-        # mssql / postgres URL handling elsewhere in this package.
+        # urlparse leaves percent-encoded characters in userinfo/path, so
+        # decode them before clickhouse-connect sees the credentials. Use
+        # ``unquote`` (not ``unquote_plus``): in a URL, ``+`` is only a space
+        # inside a query string, NOT in userinfo or the path — so a literal
+        # ``+`` in a password (e.g. ``pw+1``) must be preserved. This matches
+        # the mssql / mysql / oracle / trino URL handling in this package.
         secure = parsed.scheme == "clickhouse+https"
         # Pick the port-less default from the scheme: ClickHouse listens for
         # HTTPS on 8443 and plaintext HTTP on 8123. Defaulting an https URL to
@@ -270,14 +273,12 @@ def _build_clickhouse_client_kwargs(connection_info: Any) -> dict:
         out: dict = {
             "host": parsed.hostname,
             "port": int(parsed.port) if parsed.port else default_port,
-            "username": (
-                unquote_plus(parsed.username) if parsed.username else "default"
-            ),
-            "password": unquote_plus(parsed.password) if parsed.password else "",
+            "username": (unquote(parsed.username) if parsed.username else "default"),
+            "password": unquote(parsed.password) if parsed.password else "",
             "settings": settings,
         }
         if parsed.path and parsed.path != "/":
-            out["database"] = parsed.path.lstrip("/")
+            out["database"] = unquote(parsed.path.lstrip("/"))
         if secure:
             out["secure"] = True
         # ``settings`` already popped above, so ``out["settings"]`` survives.
diff --git a/core/wren/tests/unit/test_clickhouse_helpers.py b/core/wren/tests/unit/test_clickhouse_helpers.py
index aecd3d7288..a32227fcb6 100644
--- a/core/wren/tests/unit/test_clickhouse_helpers.py
+++ b/core/wren/tests/unit/test_clickhouse_helpers.py
@@ -42,7 +42,7 @@ def __init__(self, url: str, **extras) -> None:
 
 
 def test_clickhouse_url_decodes_username_and_password() -> None:
-    """user / password from the URL must be unquote_plus'd.
+    """user / password / database from the URL must be percent-decoded.
 
     urlparse leaves ``%40`` (``@``) and ``%20`` (space) literal in the
     userinfo, which would otherwise reach ClickHouse verbatim and fail auth.
@@ -60,6 +60,35 @@ def test_clickhouse_url_decodes_username_and_password() -> None:
     assert out["database"] == "analytics"
 
 
+def test_clickhouse_url_preserves_literal_plus_in_credentials() -> None:
+    """A literal ``+`` in userinfo is a plus, not a space.
+
+    Regression: the parser used ``unquote_plus``, which turned a literal
+    ``+`` in a password into a space and corrupted the credential. In a URL,
+    ``+`` only means space inside a query string — never in userinfo/path.
+    """
+    info = _FakeConnInfoFromUrl(
+        "clickhouse://svc+etl:pw+1@clickhouse-host:9000/an+db"
+    )
+
+    out = _build_clickhouse_client_kwargs(info)
+
+    assert out["username"] == "svc+etl"
+    assert out["password"] == "pw+1"
+    assert out["database"] == "an+db"
+
+
+def test_clickhouse_url_decodes_percent_encoded_database() -> None:
+    """A percent-encoded database name in the path must be decoded too."""
+    info = _FakeConnInfoFromUrl(
+        "clickhouse://clickhouse-host:9000/my%20analytics"
+    )
+
+    out = _build_clickhouse_client_kwargs(info)
+
+    assert out["database"] == "my analytics"
+
+
 def test_clickhouse_url_defaults_username_when_omitted() -> None:
     """When the URL has no userinfo, the default ``"default"`` user wins."""
     info = _FakeConnInfoFromUrl("clickhouse://clickhouse-host/analytics")