Remove unused grain_to_date from SqlTimeDeltaExpression

The original implementation of SqlTimeDeltaExpression had a custom
override for grain_to_date intended to support cumulative metrics.
This parameter would change the expression from a time delta to a
date_trunc. At some point we cleaned up the callsites to invoke
date_trunc directly instead of offloading this work to an overloaded
class.

This commit simply removes the confusing parameter in order to streamline
the expression rendering for time delta operations.

metricflow/sql/render/big_query.py

@@ -145,16 +145,6 @@ def render_date_part(self, date_part: DatePart) -> str:
     def visit_time_delta_expr(self, node: SqlTimeDeltaExpression) -> SqlExpressionRenderResult:
         """Render time delta for BigQuery, which requires ISO prefixing for the WEEK granularity value."""
         column = node.arg.accept(self)
-        if node.grain_to_date:
-            granularity = node.granularity
-            if granularity == TimeGranularity.WEEK:
-                granularity_value = "ISO" + granularity.value.upper()
-            else:
-                granularity_value = granularity.value
-            return SqlExpressionRenderResult(
-                sql=f"DATE_TRUNC({column.sql}, {granularity_value})",
-                bind_parameters=column.bind_parameters,
-            )
 
         return SqlExpressionRenderResult(
             sql=f"DATE_SUB(CAST({column.sql} AS {self.timestamp_data_type}), INTERVAL {node.count} {node.granularity.value})",

metricflow/sql/render/duckdb_renderer.py

@@ -37,11 +37,6 @@ def supported_percentile_function_types(self) -> Collection[SqlPercentileFunctio
     def visit_time_delta_expr(self, node: SqlTimeDeltaExpression) -> SqlExpressionRenderResult:
         """Render time delta expression for DuckDB, which requires slightly different syntax from other engines."""
         arg_rendered = node.arg.accept(self)
-        if node.grain_to_date:
-            return SqlExpressionRenderResult(
-                sql=f"DATE_TRUNC('{node.granularity.value}', {arg_rendered.sql}::timestamp)",
-                bind_parameters=arg_rendered.bind_parameters,
-            )
 
         count = node.count
         granularity = node.granularity

metricflow/sql/render/expr_renderer.py

@@ -283,11 +283,6 @@ def render_date_part(self, date_part: DatePart) -> str:
 
     def visit_time_delta_expr(self, node: SqlTimeDeltaExpression) -> SqlExpressionRenderResult:  # noqa: D
         arg_rendered = node.arg.accept(self)
-        if node.grain_to_date:
-            return SqlExpressionRenderResult(
-                sql=f"DATE_TRUNC('{node.granularity.value}', {arg_rendered.sql}::timestamp)",
-                bind_parameters=arg_rendered.bind_parameters,
-            )
 
         count = node.count
         granularity = node.granularity

metricflow/sql/render/postgres.py

@@ -40,11 +40,6 @@ def supported_percentile_function_types(self) -> Collection[SqlPercentileFunctio
     def visit_time_delta_expr(self, node: SqlTimeDeltaExpression) -> SqlExpressionRenderResult:
         """Render time delta operations for PostgreSQL, which needs custom support for quarterly granularity."""
         arg_rendered = node.arg.accept(self)
-        if node.grain_to_date:
-            return SqlExpressionRenderResult(
-                sql=f"DATE_TRUNC('{node.granularity.value}', {arg_rendered.sql}::timestamp)",
-                bind_parameters=arg_rendered.bind_parameters,
-            )
 
         count = node.count
         granularity = node.granularity

metricflow/sql/sql_exprs.py

@@ -1251,13 +1251,11 @@ def __init__(  # noqa: D
         arg: SqlExpressionNode,
         count: int,
         granularity: TimeGranularity,
-        grain_to_date: Optional[TimeGranularity] = None,
     ) -> None:
         super().__init__(node_id=self.create_unique_id(), parent_nodes=[arg])
         self._count = count
         self._time_granularity = granularity
         self._arg = arg
-        self._grain_to_date = grain_to_date
 
     @classmethod
     def id_prefix(cls) -> str:  # noqa: D
@@ -1278,10 +1276,6 @@ def description(self) -> str:  # noqa: D
     def arg(self) -> SqlExpressionNode:  # noqa: D
         return self._arg
 
-    @property
-    def grain_to_date(self) -> Optional[TimeGranularity]:  # noqa: D
-        return self._grain_to_date
-
     @property
     def count(self) -> int:  # noqa: D
         return self._count
@@ -1299,7 +1293,6 @@ def rewrite(  # noqa: D
             arg=self.arg.rewrite(column_replacements, should_render_table_alias),
             count=self.count,
             granularity=self.granularity,
-            grain_to_date=self.grain_to_date,
         )
 
     @property
@@ -1311,12 +1304,7 @@ def lineage(self) -> SqlExpressionTreeLineage:  # noqa: D
     def matches(self, other: SqlExpressionNode) -> bool:  # noqa: D
         if not isinstance(other, SqlTimeDeltaExpression):
             return False
-        return (
-            self.count == other.count
-            and self.granularity == other.granularity
-            and self.grain_to_date == other.grain_to_date
-            and self._parents_match(other)
-        )
+        return self.count == other.count and self.granularity == other.granularity and self._parents_match(other)
 
 
 class SqlCastToTimestampExpression(SqlExpressionNode):