Sql e关于指数；诚然，拥有部分索引是正确的解决方案，但即使这样，联接的第一阶段也只需要访问一个索引。除非所选的附加列的成本使得进行顺序扫描是值得的，但这是另一个问题。@LaurenzAlbe wait，这是一个误解。我不打算依赖于ORDER BY的索引——我只

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e关于指数；诚然，拥有部分索引是正确的解决方案，但即使这样，联接的第一阶段也只需要访问一个索引。除非所选的附加列的成本使得进行顺序扫描是值得的，但这是另一个问题。@LaurenzAlbe wait，这是一个误解。我不打算依赖于ORDER BY的索引——我只希望它用于数据。如果您愿意，使用覆盖索引的方式也是一样的。优点是orderby不需要访问表。我仍然希望服务器需要对索引进行完整扫描，这是给定的（添加到答案中以便更清晰）。感谢澄清。泰，我会尝试！是的，它正在工作！！！非常感谢你！在这种情况下，您的索引不能同时支持

WHERE

条件和

ORDER BY

。@LaurenzAlbe我知道，并且在建议3中提到，他们需要使用

联合

来使用索引的两列，这与您的回答类似。不过，我想我还不够清楚。

SELECT *
     FROM "refuel_request" AS "refuel_request"
     LEFT OUTER JOIN "user" AS "user" ON "refuel_request"."user_id" = "user"."user_id"
     LEFT OUTER JOIN "bill_qr" AS "bill_qr" ON "refuel_request"."bill_qr_id" = "bill_qr"."bill_qr_id"
     LEFT OUTER JOIN "car" AS "order.car" ON "refuel_request"."car_id" = "order.car"."car_id" 
     LEFT OUTER JOIN "refuel_request_status" AS "refuel_request_status" ON "refuel_request"."refuel_request_status_id" = "refuel_request_status"."refuel_request_status_id"
     WHERE
      refuel_request."refuel_request_status_id" IN ( '1', '2', '3') 
     ORDER BY "refuel_request".created_at desc
     LIMIT 10 

 LEFT OUTER JOIN "user" AS "user" ON "refuel_request"."user_id" = "user"."user_id"

 LEFT OUTER JOIN "bill_qr" AS "bill_qr" ON "refuel_request"."bill_qr_id" = 
 LEFT OUTER JOIN "car" AS "order.car" ON "refuel_request"."car_id" = 

 LEFT OUTER JOIN "refuel_request_status" AS "refuel_request_status" ON "refuel_request"."refuel_request_status_id" =

 WHERE
  refuel_request."refuel_request_status_id" IN ( '1', '2', '3') 

 ORDER BY "refuel_request".created_at desc

 refuel_request_status_id, created_at, bill_qr_id, car_id too, user_id
 ^ WHERE                   ^ ORDER     ^ used by the JOINS

CREATE INDEX idx ON refuel_request (created_at DESC)
                 WHERE refuel_request_status_id IN (1, 2, 3);

CREATE INDEX ON refuel_request (refuel_request_status_id, created_at);
CREATE INDEX ON "user" (user_id);
CREATE INDEX ON bill_qr (bill_qr_id);
CREATE INDEX ON car (car_id);
CREATE INDEX ON refuel_request_status (refuel_request_status_id);