feat: add orders & limit parameter to select_custom_fields

Author: NightMarcher

README.md

@@ -28,7 +28,7 @@ class AccountMgr(BaseManager, metaclass=DemoMetaclass):
 
 ## Some supported efficient sql
 ### **select_custom_fields**
-**without `groupbys`**
+**basic example**
 ```python
 await AccountMgr.select_custom_fields(
     fields=[
@@ -47,14 +47,16 @@ Generate sql and execute
     WHERE id IN (1, 2, 3)
 ```
 
-**with `groupbys`**
+**complex example**
 ```python
 await AccountMgr.select_custom_fields(
     fields=[
         "locale", "gender", "COUNT(1) cnt"
     ],
     wheres=["id BETWEEN 1 AND 12"],
-    groupbys=["locale", "gender"],
+    groups=["locale", "gender"],
+    orders=["locale", "-gender"],
+    limit=10,
 )
 ```
 Generate sql and execute
@@ -64,6 +66,8 @@ Generate sql and execute
     FROM account
     WHERE id BETWEEN 1 AND 12
     GROUP BY locale, gender
+    ORDER BY locale ASC, gender DESC
+    LIMIT 10
 ```
 
 ### **upsert_json_field**

examples/service/routers/account.py

@@ -56,7 +56,9 @@ async def query_group_by_locale_view(
             "locale", "gender", "COUNT(1) cnt"
         ],
         wheres=["id BETWEEN 1 AND 12"],
-        groupbys=["locale", "gender"],
+        groups=["locale", "gender"],
+        orders=["locale", "-gender"],
+        limit=10,
     )
     return {"dicts": dicts}
 

fastapi_esql/orm/base_manager.py

@@ -64,14 +64,18 @@ async def select_custom_fields(
         cls,
         fields: List[str],
         wheres: List[str],
-        groupbys: Optional[List[str]] = None,
+        groups: Optional[List[str]] = None,
+        orders: Optional[List[str]] = None,
+        limit: int = 0,
         conn: Optional[BaseDBAsyncClient] = None,
     ):
         sql = SQLizer.select_custom_fields(
             cls.table,
             fields,
             wheres,
-            groupbys,
+            groups,
+            orders,
+            limit,
         )
         conn = conn or cls.ro_conn
         return await CursorHandler.fetch_dicts(sql, conn, logger)

fastapi_esql/utils/sqlizer.py

@@ -18,6 +18,17 @@ def __init__(self, sql: str):
 
 class SQLizer:
 
+    @classmethod
+    def resolve_ordering(cls, orderings: List[str]) -> str:
+        orders = []
+        for o in orderings:
+            if o.startswith("-"):
+                order = "DESC"
+            else:
+                order = "ASC"
+            orders.append(f"{o.strip('-')} {order}")
+        return ", ".join(orders)
+
     @classmethod
     def _sqlize_value(cls, value, to_json=False) -> str:
         """
@@ -45,18 +56,30 @@ def select_custom_fields(
         table: str,
         fields: List[str],
         wheres: List[str],
-        groupbys: Optional[List[str]] = None,
+        groups: Optional[List[str]] = None,
+        orders: Optional[List[str]] = None,
+        limit: int = 0,
     ) -> Optional[str]:
         if not all([table, fields, wheres]):
             raise WrongParamsError("Please check your params")
 
-        group_by = f"GROUP BY {', '.join(groupbys)}" if groupbys else ""
-        sql = f"""
+        group_by = f"    GROUP BY {', '.join(groups)}" if groups else ""
+        order_by = f"    ORDER BY {cls.resolve_ordering(orders)}" if orders else ""
+        limit_ = f"    LIMIT {limit}" if limit else ""
+        # NOTE Doesn't support `offset` parameter due to it's bad performance
+        extras = [group_by, order_by, limit_]
+
+        sql = """
     SELECT
-        {", ".join(fields)}
-    FROM {table}
-    WHERE {" AND ".join(wheres)}
-    {group_by}"""
+        {}
+    FROM {}
+    WHERE {}
+{}""".format(
+        ", ".join(fields),
+        table,
+        " AND ".join(wheres),
+        "\n".join(extras) if extras else "",
+    )
         logger.debug(sql)
         return sql