refactor: Simplify web_overview

Use same methods as we're using on `stats_table` to calculate previous metrics. We've extracted this up to `web_analytics_query_runner`

posthog/hogql_queries/web_analytics/stats_table.py

@@ -351,52 +351,6 @@ def _main_inner_query(self, breakdown):
 
         return query
 
-    def _current_period_expression(self, field="start_timestamp"):
-        return ast.Call(
-            name="and",
-            args=[
-                ast.CompareOperation(
-                    left=ast.Field(chain=[field]),
-                    right=self.query_date_range.date_from_as_hogql(),
-                    op=ast.CompareOperationOp.GtEq,
-                ),
-                ast.CompareOperation(
-                    left=ast.Field(chain=[field]),
-                    right=self.query_date_range.date_to_as_hogql(),
-                    op=ast.CompareOperationOp.Lt,
-                ),
-            ],
-        )
-
-    def _previous_period_expression(self, field="start_timestamp"):
-        if not self.query_compare_to_date_range:
-            return ast.Constant(value=None)
-
-        return ast.Call(
-            name="and",
-            args=[
-                ast.CompareOperation(
-                    left=ast.Field(chain=[field]),
-                    right=self.query_compare_to_date_range.date_from_as_hogql(),
-                    op=ast.CompareOperationOp.GtEq,
-                ),
-                ast.CompareOperation(
-                    left=ast.Field(chain=[field]),
-                    right=self.query_compare_to_date_range.date_to_as_hogql(),
-                    op=ast.CompareOperationOp.Lt,
-                ),
-            ],
-        )
-
-    def _periods_expression(self, field="timestamp"):
-        return ast.Call(
-            name="or",
-            args=[
-                self._current_period_expression(field),
-                self._previous_period_expression(field),
-            ],
-        )
-
     def _period_comparison_tuple(self, column, alias, function_name):
         return ast.Alias(
             alias=alias,

posthog/hogql_queries/web_analytics/web_analytics_query_runner.py

@@ -70,6 +70,52 @@ def query_compare_to_date_range(self):
 
         return None
 
+    def _current_period_expression(self, field="start_timestamp"):
+        return ast.Call(
+            name="and",
+            args=[
+                ast.CompareOperation(
+                    left=ast.Field(chain=[field]),
+                    right=self.query_date_range.date_from_as_hogql(),
+                    op=ast.CompareOperationOp.GtEq,
+                ),
+                ast.CompareOperation(
+                    left=ast.Field(chain=[field]),
+                    right=self.query_date_range.date_to_as_hogql(),
+                    op=ast.CompareOperationOp.Lt,
+                ),
+            ],
+        )
+
+    def _previous_period_expression(self, field="start_timestamp"):
+        if not self.query_compare_to_date_range:
+            return ast.Constant(value=None)
+
+        return ast.Call(
+            name="and",
+            args=[
+                ast.CompareOperation(
+                    left=ast.Field(chain=[field]),
+                    right=self.query_compare_to_date_range.date_from_as_hogql(),
+                    op=ast.CompareOperationOp.GtEq,
+                ),
+                ast.CompareOperation(
+                    left=ast.Field(chain=[field]),
+                    right=self.query_compare_to_date_range.date_to_as_hogql(),
+                    op=ast.CompareOperationOp.Lt,
+                ),
+            ],
+        )
+
+    def _periods_expression(self, field="timestamp"):
+        return ast.Call(
+            name="or",
+            args=[
+                self._current_period_expression(field),
+                self._previous_period_expression(field),
+            ],
+        )
+
     @cached_property
     def pathname_property_filter(self) -> Optional[EventPropertyFilter]:
         for p in self.query.properties:

posthog/hogql_queries/web_analytics/web_overview.py

@@ -110,34 +110,19 @@ def inner_select(self) -> ast.SelectQuery:
 WHERE and(
     events.`$session_id` IS NOT NULL,
     {event_type_expr},
-    or(
-        and(timestamp >= {current_date_range_start}, timestamp < {current_date_range_end}),
-        and(timestamp >= {previous_date_range_start}, timestamp < {previous_date_range_end})
-    ),
+    {inside_timestamp_period},
     {event_properties},
     {session_properties}
 )
 GROUP BY session_id
-HAVING or(
-    and(start_timestamp >= {current_date_range_start}, start_timestamp < {current_date_range_end}),
-    and(start_timestamp >= {previous_date_range_start}, start_timestamp < {previous_date_range_end})
-)
+HAVING {inside_start_timestamp_period}
         """,
             placeholders={
                 "event_properties": self.event_properties(),
                 "session_properties": self.session_properties(),
                 "event_type_expr": self.event_type_expr,
-                # It's ok that we return ast.Constant(value=None) for previous_date_range_start
-                # and previous_date_range_end if there's no compare_to date range
-                # because HogQL will simply ignore that part of the where clause, it's that good!
-                "current_date_range_start": self.query_date_range.date_from_as_hogql(),
-                "current_date_range_end": self.query_date_range.date_to_as_hogql(),
-                "previous_date_range_start": self.query_compare_to_date_range.date_from_as_hogql()
-                if self.query_compare_to_date_range
-                else ast.Constant(value=None),
-                "previous_date_range_end": self.query_compare_to_date_range.date_to_as_hogql()
-                if self.query_compare_to_date_range
-                else ast.Constant(value=None),
+                "inside_timestamp_period": self._periods_expression("timestamp"),
+                "inside_start_timestamp_period": self._periods_expression("start_timestamp"),
             },
         )
         assert isinstance(parsed_select, ast.SelectQuery)