Merge "Add intersection method to Range class" into main

1 files changed, 46 insertions, 0 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/ranges.py b/lib/sqlalchemy/dialects/postgresql/ranges.py
index 3cf2ceb44..cefd280ea 100644
--- a/lib/sqlalchemy/dialects/postgresql/ranges.py
+++ b/lib/sqlalchemy/dialects/postgresql/ranges.py
@@ -641,6 +641,43 @@ class Range(Generic[_T]):
     def __sub__(self, other: Range[_T]) -> Range[_T]:
         return self.difference(other)
 
+    def intersection(self, other: Range[_T]) -> Range[_T]:
+        """Compute the intersection of this range with the `other`."""
+        if self.empty or other.empty or not self.overlaps(other):
+            return Range(None, None, empty=True)
+
+        slower = self.lower
+        slower_b = self.bounds[0]
+        supper = self.upper
+        supper_b = self.bounds[1]
+        olower = other.lower
+        olower_b = other.bounds[0]
+        oupper = other.upper
+        oupper_b = other.bounds[1]
+
+        if self._compare_edges(slower, slower_b, olower, olower_b) < 0:
+            rlower = olower
+            rlower_b = olower_b
+        else:
+            rlower = slower
+            rlower_b = slower_b
+
+        if self._compare_edges(supper, supper_b, oupper, oupper_b) > 0:
+            rupper = oupper
+            rupper_b = oupper_b
+        else:
+            rupper = supper
+            rupper_b = supper_b
+
+        return Range(
+            rlower,
+            rupper,
+            bounds=cast(_BoundsType, rlower_b + rupper_b),
+        )
+
+    def __mul__(self, other: Range[_T]) -> Range[_T]:
+        return self.intersection(other)
+
     def __str__(self) -> str:
         return self._stringify()
 
@@ -809,6 +846,15 @@ class AbstractRange(sqltypes.TypeEngine[Range[_T]]):
 
         __sub__ = difference
 
+        def intersection(self, other: Any) -> ColumnElement[Range[_T]]:
+            """Range expression. Returns the intersection of the two ranges.
+            Will raise an exception if the resulting range is not
+            contiguous.
+            """
+            return self.expr.op("*")(other)  # type: ignore
+
+        __mul__ = intersection
+
 
 class AbstractRangeImpl(AbstractRange[Range[_T]]):
     """Marker for AbstractRange that will apply a subclass-specific