Fix exact filters for numeric computed view columns

datasette/filters.py

@@ -3,9 +3,13 @@
 from datasette.views.base import DatasetteError
 from datasette.utils.asgi import BadRequest
 import json
+import re
 from .utils import detect_json1, escape_sqlite, path_with_removed_args
 
 
+looks_like_number_re = re.compile(r"^-?(?:\d+(?:\.\d+)?|\.\d+)$")
+
+
 @hookimpl(specname="filters_from_request")
 def where_filters(request, database, datasette):
     # This one deals with ?_where=
@@ -408,14 +412,30 @@ def selections(self):
     def has_selections(self):
         return bool(self.pairs)
 
-    def build_where_clauses(self, table):
+    def build_where_clauses(self, table, column_details=None):
         sql_bits = []
         params = {}
         i = 0
         for column, lookup, value in self.selections():
             filter = self._filters_by_key.get(lookup, None)
             if filter:
-                sql_bit, param = filter.where_clause(table, column, value, i)
+                param_name = f"p{i}"
+                if self.should_compare_with_numeric_value(
+                    column_details, column, lookup, value
+                ):
+                    numeric_comparison = (
+                        f'"{column}" = :{param_name} or '
+                        f"(typeof(\"{column}\") in ('integer', 'real') "
+                        f'and "{column}" = CAST(:{param_name} AS NUMERIC))'
+                    )
+                    sql_bit = (
+                        f"not ({numeric_comparison})"
+                        if lookup == "not"
+                        else f"({numeric_comparison})"
+                    )
+                    param = value
+                else:
+                    sql_bit, param = filter.where_clause(table, column, value, i)
                 sql_bits.append(sql_bit)
                 if param is not None:
                     if not isinstance(param, list):
@@ -425,3 +445,19 @@ def build_where_clauses(self, table):
                         params[param_id] = individual_param
                         i += 1
         return sql_bits, params
+
+    def should_compare_with_numeric_value(
+        self, column_details, column, lookup, value
+    ):
+        if lookup not in ("exact", "not"):
+            return False
+        if not isinstance(value, str):
+            return False
+        if column_details is None:
+            return False
+        column_detail = column_details.get(column)
+        if column_detail is None:
+            return False
+        if (column_detail.type or "").strip():
+            return False
+        return bool(looks_like_number_re.match(value))

datasette/views/table.py

@@ -1159,7 +1159,9 @@ async def table_view_data(
 
     # Introspect columns and primary keys for table
     pks = await db.primary_keys(table_name)
-    table_columns = await db.table_columns(table_name)
+    table_column_details = await db.table_column_details(table_name)
+    table_columns = [col.name for col in table_column_details]
+    column_details = {col.name: col for col in table_column_details}
 
     # Take ?_col= and ?_nocol= into account
     specified_columns = await _columns_to_select(table_columns, pks, request)
@@ -1203,7 +1205,9 @@ async def table_view_data(
 
     # Build where clauses from query string arguments
     filters = Filters(sorted(filter_args))
-    where_clauses, params = filters.build_where_clauses(table_name)
+    where_clauses, params = filters.build_where_clauses(
+        table_name, column_details=column_details
+    )
 
     # Execute filters_from_request plugin hooks - including the default
     # ones that live in datasette/filters.py

tests/test_table_api.py

@@ -559,6 +559,67 @@ async def test_table_filter_queries_multiple_of_same_type(ds_client):
     ] == response.json()["rows"]
 
 
+@pytest.mark.asyncio
+async def test_table_filter_view_on_numeric_computed_column(bare_ds):
+    db = bare_ds.add_memory_database("computed_column_filter")
+    await db.execute_write_script("""
+        CREATE TABLE items(
+          id INTEGER PRIMARY KEY,
+          category TEXT,
+          valid INTEGER
+        );
+
+        INSERT INTO items VALUES (1, 'a', 0);
+        INSERT INTO items VALUES (2, 'a', 1);
+        INSERT INTO items VALUES (3, 'a', 0);
+        INSERT INTO items VALUES (4, 'b', 0);
+        INSERT INTO items VALUES (5, 'b', 0);
+
+        CREATE VIEW summary AS
+          SELECT category,
+            SUM(CASE WHEN valid THEN 1 ELSE 0 END) AS valid_count,
+            SUM(CASE WHEN NOT valid THEN 1 ELSE 0 END) AS invalid_count
+          FROM items
+          GROUP BY category;
+    """)
+    response = await bare_ds.client.get(
+        "/computed_column_filter/summary.json?_shape=objects&valid_count__exact=0"
+    )
+    assert response.json()["rows"] == [
+        {"category": "b", "valid_count": 0, "invalid_count": 2}
+    ]
+
+    response = await bare_ds.client.get(
+        "/computed_column_filter/summary.json?_shape=objects&valid_count__not=0"
+    )
+    assert response.json()["rows"] == [
+        {"category": "a", "valid_count": 1, "invalid_count": 2}
+    ]
+
+
+@pytest.mark.asyncio
+async def test_table_filter_view_on_text_computed_column_preserves_exact_text(bare_ds):
+    db = bare_ds.add_memory_database("computed_text_column_filter")
+    await db.execute_write_script("""
+        CREATE TABLE items(
+          id INTEGER PRIMARY KEY,
+          code TEXT
+        );
+
+        INSERT INTO items VALUES (1, '0');
+        INSERT INTO items VALUES (2, '00');
+
+        CREATE VIEW summary AS
+          SELECT code,
+            code || '' AS code_text
+          FROM items;
+    """)
+    response = await bare_ds.client.get(
+        "/computed_text_column_filter/summary.json?_shape=objects&code_text__exact=00"
+    )
+    assert response.json()["rows"] == [{"code": "00", "code_text": "00"}]
+
+
 @pytest.mark.skipif(not detect_json1(), reason="Requires the SQLite json1 module")
 @pytest.mark.asyncio
 async def test_table_filter_json_arraycontains(ds_client):