feat(polars): add Intersection and Difference ops (#10623)

ibis/backends/polars/compiler.py

@@ -1256,6 +1256,56 @@ def execute_union(op, **kw):
     return result
 
 
+@translate.register(ops.Intersection)
+def execute_intersection(op, *, ctx, **kw):
+    left = gen_name("polars_intersect_left")
+    right = gen_name("polars_intersect_right")
+
+    ctx.register_many(
+        frames={
+            left: translate(op.left, ctx=ctx, **kw),
+            right: translate(op.right, ctx=ctx, **kw),
+        }
+    )
+
+    sql = (
+        sg.select(STAR)
+        .from_(sg.to_identifier(left, quoted=True))
+        .intersect(sg.select(STAR).from_(sg.to_identifier(right, quoted=True)))
+    )
+
+    result = ctx.execute(sql.sql(Polars), eager=False)
+
+    if op.distinct is True:
+        return result.unique()
+    return result
+
+
+@translate.register(ops.Difference)
+def execute_difference(op, *, ctx, **kw):
+    left = gen_name("polars_diff_left")
+    right = gen_name("polars_diff_right")
+
+    ctx.register_many(
+        frames={
+            left: translate(op.left, ctx=ctx, **kw),
+            right: translate(op.right, ctx=ctx, **kw),
+        }
+    )
+
+    sql = (
+        sg.select(STAR)
+        .from_(sg.to_identifier(left, quoted=True))
+        .except_(sg.select(STAR).from_(sg.to_identifier(right, quoted=True)))
+    )
+
+    result = ctx.execute(sql.sql(Polars), eager=False)
+
+    if op.distinct is True:
+        return result.unique()
+    return result
+
+
 @translate.register(ops.Hash)
 def execute_hash(op, **kw):
     # polars' hash() returns a uint64, but we want to return an int64

ibis/backends/tests/test_set_ops.py

@@ -6,7 +6,6 @@
 from pytest import param
 
 import ibis
-import ibis.common.exceptions as com
 import ibis.expr.types as ir
 from ibis import _
 from ibis.backends.tests.errors import PsycoPg2InternalError, PyDruidProgrammingError
@@ -84,7 +83,6 @@ def test_union_mixed_distinct(backend, union_subsets):
         param(True, id="distinct"),
     ],
 )
-@pytest.mark.notimpl(["polars"])
 @pytest.mark.notimpl(["druid"], raises=PyDruidProgrammingError)
 def test_intersect(backend, alltypes, df, distinct):
     a = alltypes.filter((_.id >= 5200) & (_.id <= 5210))
@@ -129,7 +127,6 @@ def test_intersect(backend, alltypes, df, distinct):
         param(True, id="distinct"),
     ],
 )
-@pytest.mark.notimpl(["polars"])
 @pytest.mark.notimpl(["druid"], raises=PyDruidProgrammingError)
 def test_difference(backend, alltypes, df, distinct):
     a = alltypes.filter((_.id >= 5200) & (_.id <= 5210))
@@ -238,7 +235,6 @@ def test_top_level_union(backend, con, alltypes, distinct, ordered):
         ),
     ],
 )
-@pytest.mark.notimpl(["polars"], raises=com.OperationNotDefinedError)
 @pytest.mark.notimpl(["druid"], raises=PyDruidProgrammingError)
 def test_top_level_intersect_difference(
     backend, con, alltypes, distinct, opname, expected, ordered