你的JoinHint為什麼不生效_ZenDei技術網路在線

本文分享自華為雲社區《你的JoinHint為什麼不生效【綻放吧！GaussDB(DWS)雲原生數倉】》，作者：你是猴子請來的救兵嗎。引言提起資料庫的Hint，幾乎每個DBA都知道這一強大功能。在GaussDB(DWS)中，Hint可以被用來干預SQL的執行計劃，但是在日常工作中，很多開發人員對 ...

本文分享自華為雲社區《你的JoinHint為什麼不生效【綻放吧！GaussDB(DWS)雲原生數倉】》，作者：你是猴子請來的救兵嗎。

引言

提起資料庫的Hint，幾乎每個DBA都知道這一強大功能。在GaussDB(DWS)中，Hint可以被用來干預SQL的執行計劃，但是在日常工作中，很多開發人員對Hint的缺乏深入瞭解，經常遇到Hint失效的情況卻又束手無策。
本次針對JoinHint從案例著手深入解析JoinHint不生效的原因，以便讀者能“知其所以然”。（本文不討論Hint的基礎語法問題）。

問題案例

內核版本 GaussDB 8.1.3

問題描述兩表關聯查詢，使用hashjoin hint干預join方式，但hint不生效

問題用例

CREATE TABLE workitem (
    language character varying(10),
    userid character varying(240),
    opiontype character varying(240),
    processinstid character varying(240),
    workitemid character varying(240),
    type_name character varying(240),
    type_code character varying(240),
    createtime timestamp without time zone,
    endtime timestamp without time zone,
    notrejecttotal numeric,
    dws_created_time timestamp without time zone
)
WITH (orientation=column, compression=low, colversion=2.0, enable_delta=false)
DISTRIBUTE BY HASH(workitemid);

CREATE  TABLE workday (
    mm timestamp with time zone,
    rn numeric
)
WITH (orientation=column, compression=low, colversion=2.0, enable_delta=false)
DISTRIBUTE BY HASH(mm);

explain
SELECT /*+ hashjoin(c d) */
    c.userid,c.type_name,c.type_code,count(1) num
FROM workitem c INNER JOIN workday d ON c.createtime = d.mm
    WHERE c.createtime >= '2023-09-01' AND c.endtime < '2023-10-01'
    GROUP BY c.userid,c.type_name,c.type_code;

WARNING:  unused hint: HashJoin(c d)
                                                                                 QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  id |                      operation                       | E-rows | E-memory | E-width | E-costs
 ----+------------------------------------------------------+--------+----------+---------+---------
   1 | ->  Row Adapter                                      |      2 |          |    1502 | 33.12
   2 |    ->  Vector Sonic Hash Aggregate                   |      2 |          |    1502 | 33.12
   3 |       ->  Vector Streaming (type: GATHER)            |      4 |          |    1502 | 33.12
   4 |          ->  Vector Sonic Hash Aggregate             |      4 | 16MB     |    1502 | 27.12
   5 |             ->  Vector Nest Loop (6,8)               |      5 | 1MB      |    1494 | 27.08
   6 |                ->  Vector Streaming(type: BROADCAST) |     14 | 2MB      |       8 | 13.68
   7 |                   ->  CStore Scan on workday d       |      7 | 1MB      |       8 | 13.05
   8 |                ->  Vector Materialize                |      5 | 16MB     |    1502 | 13.09
   9 |                   ->  CStore Scan on workitem c      |      5 | 1MB      |    1502 | 13.08

         RunTime Analyze Information
 -------------------------------------------
         "public.workitem" runtime: 25.794ms
         "public.workday" runtime: 18.098ms

                                                               Predicate Information (identified by plan id)
 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   5 --Vector Nest Loop (6,8)
         Join Filter: (c.createtime = d.mm)
   7 --CStore Scan on workday d
         Filter: (mm >= '2023-09-01 00:00:00'::timestamp without time zone)
         Pushdown Predicate Filter: (mm >= '2023-09-01 00:00:00'::timestamp without time zone)
   9 --CStore Scan on workitem c
         Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))
         Pushdown Predicate Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))

   ====== Query Summary =====
 -------------------------------
 System available mem: 4710400KB
 Query Max mem: 4710400KB
 Query estimated mem: 5271KB
(33 rows)

問題定位

嘗試關閉nestloop路徑，來驗證是否可以生成hash計劃

set enable_nestloop = off;

set enable_mergejoin = off;

set enable_hashjoin = on;

WARNING:  unused hint: HashJoin(c d)
                                                                                 QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  id |                      operation                       | E-rows | E-memory | E-width | E-costs
 ----+------------------------------------------------------+--------+----------+---------+---------
   1 | ->  Row Adapter                                      |      2 |          |    1502 | 33.12
   2 |    ->  Vector Sonic Hash Aggregate                   |      2 |          |    1502 | 33.12
   3 |       ->  Vector Streaming (type: GATHER)            |      4 |          |    1502 | 33.12
   4 |          ->  Vector Sonic Hash Aggregate             |      4 | 16MB     |    1502 | 27.12
   5 |             ->  Vector Nest Loop (6,8)               |      5 | 1MB      |    1494 | 27.08
   6 |                ->  Vector Streaming(type: BROADCAST) |     14 | 2MB      |       8 | 13.68
   7 |                   ->  CStore Scan on workday d       |      7 | 1MB      |       8 | 13.05
   8 |                ->  Vector Materialize                |      5 | 16MB     |    1502 | 13.09
   9 |                   ->  CStore Scan on workitem c      |      5 | 1MB      |    1502 | 13.08

                                                               Predicate Information (identified by plan id)
 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   5 --Vector Nest Loop (6,8)
         Join Filter: (c.createtime = d.mm)
   7 --CStore Scan on workday d
         Filter: (mm >= '2023-09-01 00:00:00'::timestamp without time zone)
         Pushdown Predicate Filter: (mm >= '2023-09-01 00:00:00'::timestamp without time zone)
   9 --CStore Scan on workitem c
         Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))
         Pushdown Predicate Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))

   ====== Query Summary =====
 -------------------------------
 System available mem: 4710400KB
 Query Max mem: 4710400KB
 Query estimated mem: 5271KB
(28 rows)

關閉nestloop路徑後，仍然生成nestloop計劃，且E-costs代價中未添加懲罰代價，說明該場景語句本身不支持hashjoin。

檢查關聯表達式(c.createtime = d.mm)，確認是否支持hashjoin。

關聯表達式為欄位關聯，不存在函數嵌套
關聯表達式兩邊數據類型為timestamp without time zone和timestamp with time zone，通過系統表pg_operator確認是否支持hashjoin。

postgres=# select * from pg_operator where oprname = '=' and oprleft = 'timestamp'::regtype and oprright = 'timestamptz'::regtype;
-[ RECORD 1 ]+-------------------------
oprname      | =
oprnamespace | 11
oprowner     | 10
oprkind      | b
oprcanmerge  | t
oprcanhash   | f
oprleft      | 1114
oprright     | 1184
oprresult    | 16
oprcom       | 2542
oprnegate    | 2539
oprcode      | timestamp_eq_timestamptz
oprrest      | eqsel
oprjoin      | eqjoinsel

通過結果確認oprcanhash為false，代表該操作符不支持hash連接；原因是，左邊數據不帶時區，右邊數據帶，在比較時要先處理時區問題，不能直接拿存儲值進行判斷。

改善辦法

通過系統表確認timestamp類型的等值關聯和timestamptz的等值關聯均支持hash連接。

postgres=# select * from pg_operator where oprname = '=' and oprleft = oprright and oprleft in('timestamp'::regtype,'timestamptz'::regtype);
-[ RECORD 1 ]+---------------
oprname      | =
oprnamespace | 11
oprowner     | 10
oprkind      | b
oprcanmerge  | t
oprcanhash   | t
oprleft      | 1184
oprright     | 1184
oprresult    | 16
oprcom       | 1320
oprnegate    | 1321
oprcode      | timestamptz_eq
oprrest      | eqsel
oprjoin      | eqjoinsel
-[ RECORD 2 ]+---------------
oprname      | =
oprnamespace | 11
oprowner     | 10
oprkind      | b
oprcanmerge  | t
oprcanhash   | t
oprleft      | 1114
oprright     | 1114
oprresult    | 16
oprcom       | 2060
oprnegate    | 2061
oprcode      | timestamp_eq
oprrest      | eqsel
oprjoin      | eqjoinsel

在關聯條件上添加類型轉換，保證兩邊類型一致，即(c.createtime：：timestamptz = d.mm)或(c.createtime = d.mm：：timestamp)。

postgres=# explain
postgres-# SELECT /*+ hashjoin(c d) */
postgres-#     c.userid,c.type_name,c.type_code,count(1) num
postgres-# FROM workitem c INNER JOIN workday d ON c.createtime::timestamptz = d.mm
postgres-#     WHERE c.createtime >= '2023-09-01' AND c.endtime < '2023-10-01'
postgres-#     GROUP BY c.userid,c.type_name,c.type_code;
                                                                                 QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  id |                      operation                       | E-rows | E-memory | E-width | E-costs
 ----+------------------------------------------------------+--------+----------+---------+---------
   1 | ->  Row Adapter                                      |      2 |          |    1502 | 34.29
   2 |    ->  Vector Sonic Hash Aggregate                   |      2 |          |    1502 | 34.29
   3 |       ->  Vector Streaming (type: GATHER)            |      4 |          |    1502 | 34.29
   4 |          ->  Vector Sonic Hash Aggregate             |      4 | 16MB     |    1502 | 28.29
   5 |             ->  Vector Sonic Hash Join (6,8)         |      5 | 16MB     |    1494 | 28.25
   6 |                ->  Vector Streaming(type: BROADCAST) |     40 | 2MB      |       8 | 15.06
   7 |                   ->  CStore Scan on workday d       |     20 | 1MB      |       8 | 13.01
   8 |                ->  CStore Scan on workitem c         |      5 | 1MB      |    1502 | 13.08

                                                               Predicate Information (identified by plan id)
 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   5 --Vector Sonic Hash Join (6,8)
         Hash Cond: (d.mm = (c.createtime)::timestamp with time zone)
   8 --CStore Scan on workitem c
         Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))
         Pushdown Predicate Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))

   ====== Query Summary =====
 -------------------------------
 System available mem: 4710400KB
 Query Max mem: 4710400KB
 Query estimated mem: 5530KB
(24 rows)

postgres=# explain
SELECT /*+ hashjoin(c d) */
    c.userid,c.type_name,c.type_code,count(1) num
FROM workitem c INNER JOIN workday d ON c.createtime = d.mm::timestamp
    WHERE c.createtime >= '2023-09-01' AND c.endtime < '2023-10-01'
    GROUP BY c.userid,c.type_name,c.type_code;
                                                                                 QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  id |                      operation                       | E-rows | E-memory | E-width | E-costs
 ----+------------------------------------------------------+--------+----------+---------+---------
   1 | ->  Row Adapter                                      |      2 |          |    1502 | 32.91
   2 |    ->  Vector Sonic Hash Aggregate                   |      2 |          |    1502 | 32.91
   3 |       ->  Vector Streaming (type: GATHER)            |      4 |          |    1502 | 32.91
   4 |          ->  Vector Sonic Hash Aggregate             |      4 | 16MB     |    1502 | 26.91
   5 |             ->  Vector Sonic Hash Join (6,8)         |      5 | 16MB     |    1494 | 26.87
   6 |                ->  Vector Streaming(type: BROADCAST) |     14 | 2MB      |       8 | 13.71
   7 |                   ->  CStore Scan on workday d       |      7 | 1MB      |       8 | 13.08
   8 |                ->  CStore Scan on workitem c         |      5 | 1MB      |    1502 | 13.08

                                                               Predicate Information (identified by plan id)
 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   5 --Vector Sonic Hash Join (6,8)
         Hash Cond: ((d.mm)::timestamp without time zone = c.createtime)
   7 --CStore Scan on workday d
         Filter: ((mm)::timestamp without time zone >= '2023-09-01 00:00:00'::timestamp without time zone)
   8 --CStore Scan on workitem c
         Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))
         Pushdown Predicate Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))

   ====== Query Summary =====
 -------------------------------
 System available mem: 4710400KB
 Query Max mem: 4710400KB
 Query estimated mem: 5530KB
(26 rows)

知識小結

實際使用過程中導致hint生效的原因很多，這裡總結排查hashjoin hint步驟以供參考:

檢查hint中的表名是否正確、是否存在重名、是否在當前層可見，此類場景通常在explain中會給出提示，自行排查即可。
判斷關聯hint中的表名是否被提升導致表名不存在，此類場景通常在explain中會給出提示

postgres=# explain
SELECT /*+ hashjoin(c d) */
    c.userid,c.type_name,c.type_code,count(1) num
FROM workitem c INNER JOIN (select * from workday where mm >= '2023-09-01') d ON c.createtime = d.mm::timestamp
    WHERE c.createtime >= '2023-09-01' AND c.endtime < '2023-10-01'
    GROUP BY c.userid,c.type_name,c.type_code;
WARNING:  Error hint: HashJoin(c d), relation name "d" is not found.
                                                                                 QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  id |                      operation                       | E-rows | E-memory | E-width | E-costs
 ----+------------------------------------------------------+--------+----------+---------+---------
   1 | ->  Row Adapter                                      |      2 |          |    1502 | 32.78
   2 |    ->  Vector Sonic Hash Aggregate                   |      2 |          |    1502 | 32.78
   3 |       ->  Vector Streaming (type: GATHER)            |      4 |          |    1502 | 32.78
   4 |          ->  Vector Sonic Hash Aggregate             |      4 | 16MB     |    1502 | 26.78
   5 |             ->  Vector Sonic Hash Join (6,8)         |      5 | 16MB     |    1494 | 26.74
   6 |                ->  Vector Streaming(type: BROADCAST) |     10 | 2MB      |       8 | 13.58
   7 |                   ->  CStore Scan on workday         |      5 | 1MB      |       8 | 13.11
   8 |                ->  CStore Scan on workitem c         |      5 | 1MB      |    1502 | 13.08

                                                               Predicate Information (identified by plan id)
 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   5 --Vector Sonic Hash Join (6,8)
         Hash Cond: ((workday.mm)::timestamp without time zone = c.createtime)
   7 --CStore Scan on workday
         Filter: ((mm >= '2023-09-01 00:00:00+08'::timestamp with time zone) AND ((mm)::timestamp without time zone >= '2023-09-01 00:00:00'::timestamp without time zone))
         Pushdown Predicate Filter: (mm >= '2023-09-01 00:00:00+08'::timestamp with time zone)
   8 --CStore Scan on workitem c
         Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))
         Pushdown Predicate Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))

   ====== Query Summary =====
 -------------------------------
 System available mem: 4710400KB
 Query Max mem: 4710400KB
 Query estimated mem: 5530KB
(27 rows)

針對此種情況，8.2.0及以上版本可以通過添加no merge hint來禁用子查詢提升從而規避hint失效問題。

通過join路徑參數驗證目標路徑是否可生效。

--如通過關閉其他路徑參數來驗證某一路徑是否可達
set enable_nestloop = off;
set enable_mergejoin = off;
set enable_hashjoin = on;

檢查關聯條件中是否存在volatile函數。

postgres=# create or replace function gettimediff(timestamp) returns interval language sql as 'select $1-timeofday()::timestamp' volatile;
CREATE FUNCTION
postgres=# explain
SELECT /*+ hashjoin(c d) */
    c.userid,c.type_name,c.type_code,count(1) num
FROM workitem c INNER JOIN workday d ON gettimediff(c.createtime) = gettimediff(d.mm::timestamp)
    WHERE c.createtime >= '2023-09-01' AND c.endtime < '2023-10-01'
    GROUP BY c.userid,c.type_name,c.type_code;
WARNING:  unused hint: HashJoin(c d)
                                                                               QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  id |                          operation                          | E-rows | E-width | E-costs
 ----+-------------------------------------------------------------+--------+---------+---------
   1 | ->  HashAggregate                                           |      5 |    1502 | 3.10
   2 |    ->  Nested Loop (3,4)                                    |      5 |    1494 | 3.00
   3 |       ->  Data Node Scan on workitem "_REMOTE_TABLE_QUERY_" |      5 |    1502 | 0.00
   4 |       ->  Data Node Scan on workday "_REMOTE_TABLE_QUERY_"  |     20 |       8 | 0.00

                                                              Predicate Information (identified by plan id)
 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------
   2 --Nested Loop (3,4)
         Join Filter: ((c.createtime - (timeofday())::timestamp without time zone) = ((d.mm)::timestamp without time zone - (timeofday())::timestamp without time zone))
(11 rows)

檢查關聯條件中兩表欄位是否在等號兩側，若不是則進行調整。

postgres=# explain
SELECT /*+ hashjoin(c d) */
    c.userid,c.type_name,c.type_code,count(1) num
FROM workitem c INNER JOIN workday d ON ifnull(c.createtime,d.mm) = now()
    WHERE c.createtime >= '2023-09-01' AND c.endtime < '2023-10-01'
    GROUP BY c.userid,c.type_name,c.type_code;
WARNING:  unused hint: HashJoin(c d)
                                                                                 QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  id |                      operation                       | E-rows | E-memory | E-width | E-costs
 ----+------------------------------------------------------+--------+----------+---------+---------
   1 | ->  Row Adapter                                      |      1 |          |    1502 | 35.37
   2 |    ->  Vector Sonic Hash Aggregate                   |      1 |          |    1502 | 35.37
   3 |       ->  Vector Streaming (type: GATHER)            |      2 |          |    1502 | 35.37
   4 |          ->  Vector Sonic Hash Aggregate             |      2 | 16MB     |    1502 | 29.37
   5 |             ->  Vector Nest Loop (6,8)               |      2 | 1MB      |    1494 | 29.35
   6 |                ->  Vector Streaming(type: BROADCAST) |     40 | 2MB      |       8 | 15.06
   7 |                   ->  CStore Scan on workday d       |     20 | 1MB      |       8 | 13.01
   8 |                ->  Vector Materialize                |      5 | 16MB     |    1502 | 13.09
   9 |                   ->  CStore Scan on workitem c      |      5 | 1MB      |    1502 | 13.08

                                                               Predicate Information (identified by plan id)
 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   5 --Vector Nest Loop (6,8)
         Join Filter: (COALESCE((c.createtime)::timestamp with time zone, d.mm) = now())
   9 --CStore Scan on workitem c
         Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))
         Pushdown Predicate Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))

   ====== Query Summary =====
 -------------------------------
 System available mem: 4710400KB
 Query Max mem: 4710400KB
 Query estimated mem: 5275KB
(25 rows)

檢查關聯條件是否為等值關聯，若不是則進行調整。

postgres=# explain
SELECT /*+ hashjoin(c d) */
    c.userid,c.type_name,c.type_code,count(1) num
FROM workitem c INNER JOIN workday d ON c.createtime::timestamptz > d.mm
    WHERE c.createtime >= '2023-09-01' AND c.endtime < '2023-10-01'
    GROUP BY c.userid,c.type_name,c.type_code;
WARNING:  unused hint: HashJoin(c d)
                                                                                 QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  id |                      operation                       | E-rows | E-memory | E-width | E-costs
 ----+------------------------------------------------------+--------+----------+---------+---------
   1 | ->  Row Adapter                                      |      5 |          |    1502 | 35.41
   2 |    ->  Vector Sonic Hash Aggregate                   |      5 |          |    1502 | 35.41
   3 |       ->  Vector Streaming (type: GATHER)            |     10 |          |    1502 | 35.41
   4 |          ->  Vector Sonic Hash Aggregate             |     10 | 16MB     |    1502 | 29.41
   5 |             ->  Vector Nest Loop (6,8)               |     33 | 1MB      |    1494 | 29.20
   6 |                ->  Vector Streaming(type: BROADCAST) |     40 | 2MB      |       8 | 15.06
   7 |                   ->  CStore Scan on workday d       |     20 | 1MB      |       8 | 13.01
   8 |                ->  Vector Materialize                |      5 | 16MB     |    1502 | 13.09
   9 |                   ->  CStore Scan on workitem c      |      5 | 1MB      |    1502 | 13.08

                                                               Predicate Information (identified by plan id)
 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   5 --Vector Nest Loop (6,8)
         Join Filter: ((c.createtime)::timestamp with time zone > d.mm)
   9 --CStore Scan on workitem c
         Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))
         Pushdown Predicate Filter: ((createtime >= '2023-09-01 00:00:00'::timestamp without time zone) AND (endtime < '2023-10-01 00:00:00'::timestamp without time zone))

   ====== Query Summary =====
 -------------------------------
 System available mem: 4710400KB
 Query Max mem: 4710400KB
 Query estimated mem: 5281KB
(25 rows)

檢查關聯關係兩側的數據類型，並通過pg_operator.oprcanhash確認是否支持hash連接，若不支持則需改寫為支持的操作符。

postgres=# select * from pg_operator where oprname = '=' and oprleft = 'timestamp'::regtype and oprright = 'timestamptz'::regtype;
-[ RECORD 1 ]+-------------------------
oprname      | =
oprnamespace | 11
oprowner     | 10
oprkind      | b
oprcanmerge  | t
oprcanhash   | f
oprleft      | 1114
oprright     | 1184
oprresult    | 16
oprcom       | 2542
oprnegate    | 2539
oprcode      | timestamp_eq_timestamptz
oprrest      | eqsel
oprjoin      | eqjoinsel

如果是指定join順序的hint，如leading(c e),會存在邏輯本身衝突導致hint失敗的情況。

postgres=# explain SELECT /*+ leading(c e) */
    c.userid,c.type_name,c.type_code,count(1) num
FROM workitem c LEFT JOIN workday d ON c.createtime = d.mm LEFT JOIN workday e ON d.mm = e.mm
    WHERE c.createtime >= '2023-09-01' AND c.endtime < '2023-10-01'
    GROUP BY c.userid,c.type_name,c.type_code;
WARNING:  unused hint: Leading(c e)