feat(api): add DateValue.epoch api for computing days since epoch

ibis/backends/polars/compiler.py

@@ -1442,3 +1442,12 @@ def execute_group_concat(op, **kw):
         arg = arg.sort_by(keys, descending=descending)
 
     return pl.when(arg.count() > 0).then(arg.str.join(sep)).otherwise(None)
+
+
+@translate.register(ops.DateDelta)
+def execute_date_delta(op, **kw):
+    left = translate(op.left, **kw)
+    right = translate(op.right, **kw)
+    delta = left - right
+    method_name = f"total_{_literal_value(op.part)}s"
+    return getattr(delta.dt, method_name)()

ibis/backends/sql/compilers/impala.py

@@ -29,7 +29,6 @@
         ops.ArrayPosition,
         ops.Array,
         ops.Covariance,
-        ops.DateDelta,
         ops.ExtractDayOfYear,
         ops.Levenshtein,
         ops.Map,
@@ -314,5 +313,16 @@
             return self.cast(sign, dtype)
         return sign
 
+    def visit_DateDelta(self, op, *, left, right, part):
+        if not isinstance(part, sge.Literal):
+            raise com.UnsupportedOperationError(
+                "Only literal `part` values are supported for date delta"
+            )
+        if part.this != "day":
+            raise com.UnsupportedOperationError(
+                f"Only 'day' part is supported for date delta in the {self.dialect} backend"
+            )
+        return self.f.datediff(left, right)
+
 
 compiler = ImpalaCompiler()

ibis/backends/sql/compilers/oracle.py

@@ -63,7 +63,6 @@
         ops.Bucket,
         ops.TimestampBucket,
         ops.TimeDelta,
-        ops.DateDelta,
         ops.TimestampDelta,
         ops.TimestampFromYMDHMS,
         ops.TimeFromHMS,
@@ -475,5 +474,22 @@
     def visit_IntervalFromInteger(self, op, *, arg, unit):
         return self._value_to_interval(arg, unit)
 
+    def visit_DateFromYMD(self, op, *, year, month, day):
+        year = self.f.lpad(year, 4, "0")
+        month = self.f.lpad(month, 2, "0")
+        day = self.f.lpad(day, 2, "0")
+        return self.f.to_date(self.f.concat(year, month, day), "FXYYYYMMDD")
+
+    def visit_DateDelta(self, op, *, left, right, part):
+        if not isinstance(part, sge.Literal):
+            raise com.UnsupportedOperationError(
+                "Only literal `part` values are supported for date delta"
+            )
+        if part.this != "day":
+            raise com.UnsupportedOperationError(
+                f"Only 'day' part is supported for date delta in the {self.dialect} backend"
+            )
+        return left - right
+
 
 compiler = OracleCompiler()

ibis/backends/sql/compilers/risingwave.py

@@ -19,7 +19,6 @@ class RisingWaveCompiler(PostgresCompiler):
 
     UNSUPPORTED_OPS = (
         ops.Arbitrary,
-        ops.DateFromYMD,
         ops.Mode,
         ops.RandomUUID,
         ops.MultiQuantile,

ibis/backends/sql/compilers/sqlite.py

@@ -59,7 +59,6 @@
         ops.StringToDate,
         ops.StringToTimestamp,
         ops.TimeDelta,
-        ops.DateDelta,
         ops.TimestampDelta,
         ops.TryCast,
     )
@@ -531,5 +530,16 @@
             raise com.UnsupportedBackendType(f"Unsupported type: {dtype!r}")
         return super().visit_NonNullLiteral(op, value=value, dtype=dtype)
 
+    def visit_DateDelta(self, op, *, left, right, part):
+        if not isinstance(part, sge.Literal):
+            raise com.UnsupportedOperationError(
+                "Only literal `part` values are supported for date delta"
+            )
+        if part.this != "day":
+            raise com.UnsupportedOperationError(
+                f"Only 'day' part is supported for date delta in the {self.dialect} backend"
+            )
+        return self.f._ibis_date_delta(left, right)
+
 
 compiler = SQLiteCompiler()

ibis/backends/sqlite/udf.py

@@ -5,6 +5,7 @@
 import math
 import operator
 from collections import defaultdict
+from datetime import date
 from typing import TYPE_CHECKING, Any, NamedTuple
 from urllib.parse import parse_qs, urlsplit
 from uuid import uuid4
@@ -357,6 +358,12 @@ def _ibis_extract_user_info(url):
     return f"{username}:{password}"
 
 
+@udf
+def _ibis_date_delta(left, right):
+    delta = date.fromisoformat(left) - date.fromisoformat(right)
+    return delta.days
+
+
 class _ibis_var:
     def __init__(self, offset):
         self.mean = 0.0

ibis/backends/tests/test_temporal.py

@@ -1474,11 +1474,7 @@ def test_today_from_projection(alltypes):
 
 
 @pytest.mark.notimpl(
-    ["pandas", "dask", "exasol", "risingwave", "druid"],
-    raises=com.OperationNotDefinedError,
-)
-@pytest.mark.notimpl(
-    ["oracle"], raises=OracleDatabaseError, reason="ORA-00936 missing expression"
+    ["pandas", "dask", "exasol", "druid"], raises=com.OperationNotDefinedError
 )
 def test_date_literal(con, backend):
     expr = ibis.date(2022, 2, 4)
@@ -1709,11 +1705,7 @@ def test_interval_literal(con, backend):
 
 
 @pytest.mark.notimpl(
-    ["pandas", "dask", "exasol", "risingwave", "druid"],
-    raises=com.OperationNotDefinedError,
-)
-@pytest.mark.notimpl(
-    ["oracle"], raises=OracleDatabaseError, reason="ORA-00936: missing expression"
+    ["pandas", "dask", "exasol", "druid"], raises=com.OperationNotDefinedError
 )
 def test_date_column_from_ymd(backend, con, alltypes, df):
     c = alltypes.timestamp_col
@@ -1975,16 +1967,7 @@ def test_timestamp_precision_output(con, ts, scale, unit):
 
 
 @pytest.mark.notimpl(
-    [
-        "dask",
-        "datafusion",
-        "druid",
-        "impala",
-        "oracle",
-        "pandas",
-        "polars",
-    ],
-    raises=com.OperationNotDefinedError,
+    ["dask", "datafusion", "druid", "pandas"], raises=com.OperationNotDefinedError
 )
 @pytest.mark.parametrize(
     ("start", "end", "unit", "expected"),
@@ -2006,7 +1989,10 @@ def test_timestamp_precision_output(con, ts, scale, unit):
                     reason="postgres doesn't have any easy way to accurately compute the delta in specific units",
                     raises=com.OperationNotDefinedError,
                 ),
-                pytest.mark.notimpl(["exasol"], raises=com.OperationNotDefinedError),
+                pytest.mark.notimpl(
+                    ["exasol", "polars", "sqlite", "oracle", "impala"],
+                    raises=com.OperationNotDefinedError,
+                ),
             ],
         ),
         param(ibis.date("1992-09-30"), ibis.date("1992-10-01"), "day", 1, id="date"),
@@ -2027,12 +2013,14 @@ def test_timestamp_precision_output(con, ts, scale, unit):
                     raises=com.OperationNotDefinedError,
                     reason="timestampdiff rounds after subtraction and mysql doesn't have a date_trunc function",
                 ),
-                pytest.mark.notimpl(["exasol"], raises=com.OperationNotDefinedError),
+                pytest.mark.notimpl(
+                    ["exasol", "polars", "sqlite", "oracle", "impala"],
+                    raises=com.OperationNotDefinedError,
+                ),
             ],
         ),
     ],
 )
-@pytest.mark.notimpl(["sqlite"], raises=com.OperationNotDefinedError)
 def test_delta(con, start, end, unit, expected):
     expr = end.delta(start, unit)
     assert con.execute(expr) == expected
@@ -2297,3 +2285,15 @@ def test_date_scalar(con, value, func):
     assert isinstance(result, datetime.date)
 
     assert result == datetime.date.fromisoformat(value)
+
+
+@pytest.mark.notyet(
+    ["dask", "datafusion", "pandas", "druid", "exasol"],
+    raises=com.OperationNotDefinedError,
+)
+def test_simple_unix_date_offset(con):
+    d = ibis.date("2023-04-07")
+    expr = d.epoch_days()
+    result = con.execute(expr)
+    delta = datetime.date(2023, 4, 7) - datetime.date(1970, 1, 1)
+    assert result == delta.days

ibis/expr/types/temporal.py

@@ -474,6 +474,42 @@ def delta(
         """
         return ops.DateDelta(left=self, right=other, part=part).to_expr()
 
+    def epoch_days(self) -> ir.IntegerValue:
+        """Return the number of days since the UNIX epoch date.
+
+        Examples
+        --------
+        >>> import ibis
+        >>> ibis.options.interactive = True
+        >>> date = ibis.date(2020, 1, 1)
+        >>> date
+        ┌────────────┐
+        │ 2020-01-01 │
+        └────────────┘
+        >>> date.epoch_days()
+        ┌───────┐
+        │ 18262 │
+        └───────┘
+        >>> t = date.name("date_col").as_table()
+        >>> t
+        ┏━━━━━━━━━━━━┓
+        ┃ date_col   ┃
+        ┡━━━━━━━━━━━━┩
+        │ date       │
+        ├────────────┤
+        │ 2020-01-01 │
+        └────────────┘
+        >>> t.mutate(epoch=t.date_col.epoch_days())
+        ┏━━━━━━━━━━━━┳━━━━━━━┓
+        ┃ date_col   ┃ epoch ┃
+        ┡━━━━━━━━━━━━╇━━━━━━━┩
+        │ date       │ int64 │
+        ├────────────┼───────┤
+        │ 2020-01-01 │ 18262 │
+        └────────────┴───────┘
+        """
+        return self.delta(ibis.date(1970, 1, 1), "day")
+
 
 @public
 class DateScalar(Scalar, DateValue):