From 894ce90d01df72c2fdb8c24af5b2b9c4bad8412a Mon Sep 17 00:00:00 2001
From: Phillip Cloud <417981+cpcloud@users.noreply.github.com>
Date: Fri, 20 May 2022 10:56:09 -0700
Subject: [PATCH] feat(duckdb): implement approx_median

---
 ibis/backends/duckdb/registry.py   | 5 +++++
 ibis/backends/tests/test_client.py | 1 +
 2 files changed, 6 insertions(+)

diff --git a/ibis/backends/duckdb/registry.py b/ibis/backends/duckdb/registry.py
index 7a9a3308556d..608965ba503f 100644
--- a/ibis/backends/duckdb/registry.py
+++ b/ibis/backends/duckdb/registry.py
@@ -167,6 +167,11 @@ def _regex_extract(t, expr):
         ops.RegexExtract: _regex_extract,
         ops.RegexReplace: fixed_arity(sa.func.regexp_replace, 3),
         ops.StringContains: fixed_arity(sa.func.contains, 2),
+        ops.CMSMedian: reduction(
+            # without inline text, duckdb fails with
+            # RuntimeError: INTERNAL Error: Invalid PhysicalType for GetTypeIdSize # noqa: E501
+            lambda arg: sa.func.approx_quantile(arg, sa.text(str(0.5)))
+        ),
         ops.HLLCardinality: reduction(sa.func.approx_count_distinct),
     }
 )
diff --git a/ibis/backends/tests/test_client.py b/ibis/backends/tests/test_client.py
index 3b90b061b18c..21686cb12ad2 100644
--- a/ibis/backends/tests/test_client.py
+++ b/ibis/backends/tests/test_client.py
@@ -337,6 +337,7 @@ def test_verify(ddl_backend, ddl_con):
         assert ddl_backend.api.verify(expr)
 
 
+@pytest.mark.never(["duckdb"], reason="duckdb supports approximate median")
 def test_not_verify(alchemy_con, alchemy_backend):
     # There is no expression that can't be compiled to any backend
     # Testing `not verify()` only for an expression not supported in postgres