Fix motherduck bug (#858)

data_diff/databases/base.py

@@ -1046,6 +1046,7 @@ def query_table_schema(self, path: DbPath) -> Dict[str, RawColumnInfo]:
               accessing the schema using a SQL query.
         """
         rows = self.query(self.select_table_schema(path), list, log_message=path)
+
         if not rows:
             raise RuntimeError(f"{self.name}: Table '{'.'.join(path)}' does not exist, or has no columns")
 
@@ -1060,6 +1061,7 @@ def query_table_schema(self, path: DbPath) -> Dict[str, RawColumnInfo]:
             )
             for r in rows
         }
+
         assert len(d) == len(rows)
         return d
 

data_diff/databases/duckdb.py

@@ -167,12 +167,16 @@ def select_table_schema(self, path: DbPath) -> str:
         database, schema, table = self._normalize_table_path(path)
 
         info_schema_path = ["information_schema", "columns"]
+
         if database:
             info_schema_path.insert(0, database)
+            dynamic_database_clause = f"'{database}'"
+        else:
+            dynamic_database_clause = "current_catalog()"
 
         return (
             f"SELECT column_name, data_type, datetime_precision, numeric_precision, numeric_scale FROM {'.'.join(info_schema_path)} "
-            f"WHERE table_name = '{table}' AND table_schema = '{schema}'"
+            f"WHERE table_name = '{table}' AND table_schema = '{schema}' and table_catalog = {dynamic_database_clause}"
         )
 
     def _normalize_table_path(self, path: DbPath) -> DbPath:

tests/test_duckdb.py

@@ -0,0 +1,42 @@
+import unittest
+from data_diff.databases import duckdb as duckdb_differ
+import os
+import uuid
+
+test_duckdb_filepath = str(uuid.uuid4()) + ".duckdb"
+
+
+class TestDuckDBTableSchemaMethods(unittest.TestCase):
+    def setUp(self):
+        # Create a new duckdb file
+        self.duckdb_conn = duckdb_differ.DuckDB(filepath=test_duckdb_filepath)
+
+    def tearDown(self):
+        # Optional: delete file after tests
+        os.remove(test_duckdb_filepath)
+
+    def test_normalize_table_path(self):
+        self.assertEqual(self.duckdb_conn._normalize_table_path(("test_table",)), (None, "main", "test_table"))
+        self.assertEqual(
+            self.duckdb_conn._normalize_table_path(("test_schema", "test_table")), (None, "test_schema", "test_table")
+        )
+        self.assertEqual(
+            self.duckdb_conn._normalize_table_path(("test_database", "test_schema", "test_table")),
+            ("test_database", "test_schema", "test_table"),
+        )
+
+        with self.assertRaises(ValueError):
+            self.duckdb_conn._normalize_table_path(("test_database", "test_schema", "test_table", "extra"))
+
+    def test_select_table_schema(self):
+        db_path = ("test_table",)
+        expected_sql = "SELECT column_name, data_type, datetime_precision, numeric_precision, numeric_scale FROM information_schema.columns WHERE table_name = 'test_table' AND table_schema = 'main' and table_catalog = current_catalog()"
+        self.assertEqual(self.duckdb_conn.select_table_schema(db_path), expected_sql)
+
+        db_path = ("custom_schema", "test_table")
+        expected_sql = "SELECT column_name, data_type, datetime_precision, numeric_precision, numeric_scale FROM information_schema.columns WHERE table_name = 'test_table' AND table_schema = 'custom_schema' and table_catalog = current_catalog()"
+        self.assertEqual(self.duckdb_conn.select_table_schema(db_path), expected_sql)
+
+        db_path = ("custom_db", "custom_schema", "test_table")
+        expected_sql = "SELECT column_name, data_type, datetime_precision, numeric_precision, numeric_scale FROM custom_db.information_schema.columns WHERE table_name = 'test_table' AND table_schema = 'custom_schema' and table_catalog = 'custom_db'"
+        self.assertEqual(self.duckdb_conn.select_table_schema(db_path), expected_sql)