fix(charts): handle PostgreSQL INTERVAL type in bar and pie charts (#34513)

Co-authored-by: Claude <noreply@anthropic.com>

tests/unit_tests/db_engine_specs/test_postgres.py

@@ -15,14 +15,14 @@
 # specific language governing permissions and limitations
 # under the License.
 
-from datetime import datetime
+from datetime import datetime, timedelta
 from typing import Any, Optional
 from unittest.mock import MagicMock
 
 import pytest
 from pytest_mock import MockerFixture
 from sqlalchemy import column, types
-from sqlalchemy.dialects.postgresql import DOUBLE_PRECISION, ENUM, JSON
+from sqlalchemy.dialects.postgresql import DOUBLE_PRECISION, ENUM, INTERVAL, JSON
 from sqlalchemy.engine.interfaces import Dialect
 from sqlalchemy.engine.url import make_url
 
@@ -87,6 +87,8 @@ def test_convert_dttm(
         ("TIME", types.Time, None, GenericDataType.TEMPORAL, True),
         # Boolean
         ("BOOLEAN", types.Boolean, None, GenericDataType.BOOLEAN, False),
+        # Interval (mapped to NUMERIC for chart rendering)
+        ("INTERVAL", INTERVAL, None, GenericDataType.NUMERIC, False),
     ],
 )
 def test_get_column_spec(
@@ -366,3 +368,38 @@ class TestRedshiftDetection:
         spec.update_params_from_encrypted_extra(database, params)
 
         assert "pool_events" not in params
+
+
+def test_interval_type_mutator() -> None:
+    """
+    DB Eng Specs (postgres): Test INTERVAL type mutator
+
+    INTERVAL values are converted to milliseconds so users can apply
+    the built-in "DURATION" number format for human-readable display.
+    """
+    mutator = spec.column_type_mutators[INTERVAL]
+
+    # Timedelta conversion — the only path psycopg2/psycopg3 actually
+    # exercises. Result is in milliseconds for compatibility with the
+    # DURATION formatter.
+    td = timedelta(days=1, hours=2, minutes=30, seconds=45)
+    assert mutator(td) == 95445000.0  # (1*86400 + 2*3600 + 30*60 + 45) * 1000
+
+    # Zero duration
+    assert mutator(timedelta(0)) == 0.0
+
+    # Negative interval
+    assert mutator(timedelta(days=-1)) == -86400000.0
+
+    # None preserves NULL semantics (not converted to 0)
+    assert mutator(None) is None
+
+    # Unexpected non-timedelta types fall through to the defensive
+    # `return None` (and emit a warning) rather than producing a
+    # mixed-type column.
+    assert mutator("1 day 02:30:45") is None
+    assert mutator("P1DT2H30M45S") is None
+    assert mutator(12345) is None
+    assert mutator(True) is None
+    assert mutator([1, 2, 3]) is None
+    assert mutator({"days": 1}) is None