implement FROM-TO

src/questdb_connect/compilers.py

@@ -41,6 +41,12 @@ def visit_sample_by(self, sample_by, **kw):
         else:
             text = f"SAMPLE BY {sample_by.value}"
 
+        if sample_by.from_timestamp:
+            # Format datetime to ISO format that QuestDB expects
+            text += f" FROM '{sample_by.from_timestamp.isoformat()}'"
+        if sample_by.to_timestamp:
+            text += f" TO '{sample_by.to_timestamp.isoformat()}'"
+
         # Add FILL if specified
         if sample_by.fill is not None:
             if isinstance(sample_by.fill, str):

src/questdb_connect/dml.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from datetime import datetime, date
 from typing import TYPE_CHECKING, Any, Optional, Sequence, Union
 
 from sqlalchemy import select as sa_select
@@ -24,13 +25,17 @@ def __init__(
             align_to: str = "CALENDAR",  # default per docs
             timezone: Optional[str] = None,
             offset: Optional[str] = None,
+            from_timestamp: Optional[Union[datetime, date]] = None,
+            to_timestamp: Optional[Union[datetime, date]] = None
     ):
         self.value = value
         self.unit = unit.lower() if unit else None
         self.fill = fill
         self.align_to = align_to.upper()
         self.timezone = timezone
         self.offset = offset
+        self.from_timestamp = from_timestamp
+        self.to_timestamp = to_timestamp
 
     def __str__(self) -> str:
         if self.unit:
@@ -67,6 +72,8 @@ def sample_by(
             align_to: str = "CALENDAR",
             timezone: Optional[str] = None,
             offset: Optional[str] = None,
+            from_timestamp: Optional[Union[datetime, date]] = None,
+            to_timestamp: Optional[Union[datetime, date]] = None,
     ) -> QDBSelect:
         """Add a SAMPLE BY clause.
 
@@ -84,7 +91,7 @@ def sample_by(
 
         # Set the sample by clause
         s._sample_by_clause = SampleByClause(
-            value, unit, fill, align_to, timezone, offset
+            value, unit, fill, align_to, timezone, offset, from_timestamp, to_timestamp
         )
         return s
 

tests/test_dialect.py

@@ -416,6 +416,108 @@ def test_bulk_insert(test_engine, test_model):
         assert collect_select_all_raw_connection(test_engine, expected_rows=num_rows) == expected
 
 
+def test_sample_by_from_to(test_engine, test_model):
+    """Test SAMPLE BY with FROM-TO extension."""
+    base_ts = datetime.datetime(2023, 4, 12, 0, 0, 0)
+    day_before = base_ts - datetime.timedelta(days=1)
+    day_after = base_ts + datetime.timedelta(days=1)
+    session = Session(test_engine)
+    try:
+        num_rows = 6 # 6 hours only
+        models = [
+            test_model(
+                col_int=idx,
+                col_ts=base_ts + datetime.timedelta(hours=idx),
+            ) for idx in range(num_rows)
+        ]
+
+        session.bulk_save_objects(models)
+        session.commit()
+
+        metadata = sqla.MetaData()
+        table = sqla.Table(ALL_TYPES_TABLE_NAME, metadata, autoload_with=test_engine)
+        wait_until_table_is_ready(test_engine, ALL_TYPES_TABLE_NAME, len(models))
+
+        with test_engine.connect() as conn:
+            # Test FROM-TO with FILL
+            query = (
+                questdb_connect.select(
+                    table.c.col_ts,
+                    sqla.func.avg(table.c.col_int).label('avg_int')
+                )
+                .sample_by(
+                    1, 'h',
+                    fill="NULL",
+                    from_timestamp=day_before,  # day before data starts
+                    to_timestamp=day_after  # day after data ends
+                )
+            )
+            result = conn.execute(query)
+            rows = result.fetchall()
+
+            assert len(rows) == 48  # 48 hours in total
+
+            # First rows should be NULL (before our data starts)
+            assert rows[0].avg_int is None
+            assert rows[1].avg_int is None
+            assert rows[2].avg_int is None
+            assert rows[3].avg_int is None
+
+            # Middle rows should have data
+            assert any(row.avg_int is not None for row in rows[4:-4])
+
+            # Last rows should be NULL (after our data ends)
+            assert rows[-4].avg_int is None
+            assert rows[-3].avg_int is None
+            assert rows[-2].avg_int is None
+            assert rows[-1].avg_int is None
+
+            # Test FROM only
+            query = (
+                questdb_connect.select(
+                    table.c.col_ts,
+                    sqla.func.avg(table.c.col_int).label('avg_int')
+                )
+                .sample_by(
+                    1, 'h',
+                    fill="NULL",
+                    from_timestamp=day_before  # day before data starts
+                )
+            )
+            result = conn.execute(query)
+            rows = result.fetchall()
+
+            # First rows should be NULL
+            assert rows[0].avg_int is None
+            assert rows[1].avg_int is None
+            assert rows[2].avg_int is None
+            assert rows[3].avg_int is None
+
+            # Test TO only
+            query = (
+                questdb_connect.select(
+                    table.c.col_ts,
+                    sqla.func.avg(table.c.col_int).label('avg_int')
+                )
+                .sample_by(
+                    1, 'h',
+                    fill="NULL",
+                    to_timestamp=day_after  # day after data ends
+                )
+            )
+            result = conn.execute(query)
+            rows = result.fetchall()
+
+            # Last rows should be NULL
+            assert rows[-4].avg_int is None
+            assert rows[-3].avg_int is None
+            assert rows[-2].avg_int is None
+            assert rows[-1].avg_int is None
+
+    finally:
+        if session:
+            session.close()
+
 def test_sample_by_options(test_engine, test_model):
     """Test SAMPLE BY with ALIGN TO and FILL options."""
     base_ts = datetime.datetime(2023, 4, 12, 0, 0, 0)