select Customers.cust_name,Orders.oder_num from Customers inner join Orders on Customers.cust_id == Orders.cust_id order by Customers.cust_name desc这句SQL有什么语法错误

这句 SQL 语句看起来是正确的，但是有一个小错误。在 SQL 中，"==" 不是用于比较相等的运算符，而是 " = "。因此，正确的 SQL 语句应该是：

SELECT Customers.cust_name, Orders.oder_num 
FROM Customers 
INNER JOIN Orders ON Customers.cust_id = Orders.cust_id 
ORDER BY Customers.cust_name DESC

这将按照顾客的名称（以降序排列）和订单号选择顾客和订单信息，并将它们结合在一起。

相关问题

select * from ( select row_.*, rownum rownum_ from ( select * from ( select distinct OB.BUSI_ORDER_ID, 0 as HIS_ID, OB.BUSI_CODE, OB.CUST_ID, OB.CEASE_REASON, OB.ORDER_STATE, OB.CHANNEL_TYPE, ob.user_id, OB.IS_BATCH_ORDER, OB.APPLICATION_ID, OB.CREATE_DATE, OB.DONE_DATE, OB.EFF_DATE, OB.EXP_DATE, OB.OPER_ID, OB.ORG_ID, OB.REGION_ID, OB.NOTE, OB.PROCESS_STATE, nvl(oi.cust_name, ic.cust_name) cust_name, nvl(oc.icc_id, iu.icc_id) icc_id, nvl(oc.svc_num, iu.svc_num) svc_num, icp.cust_name parent_cust_name, icp.cust_id parent_cust_id, ol.order_list_id from ord_busi ob left join ord_offer oo on oo.busi_order_id = ob.busi_order_id and ob.user_id = oo.user_id left join info_user iu on oo.user_id = iu.user_id left join info_cust ic on ob.cust_id = ic.cust_id left join ord_cust oi on ob.cust_id = oi.cust_id and ob.busi_order_id = oi.busi_order_id left join info_cust icp on nvl(ic.parent_cust_id, oi.parent_cust_id) = icp.cust_id left join ( SELECT * FROM ord_user WHERE user_order_id IN ( SELECT MAX(user_order_id) user_order_id FROM ord_user GROUP BY busi_order_id,user_id ) ) oc on ob.user_id = oc.user_id and ob.busi_order_id = oc.busi_order_id left join ord_list ol on ob.busi_order_id = ol.busi_order_id WHERE 1 = 1 and OB.CUST_ID IN( SELECT DISTINCT CUST_ID FROM (SELECT CUST_ID, PARENT_CUST_ID FROM INFO_CUST UNION SELECT CUST_ID, PARENT_CUST_ID FROM ORD_CUST) TMP START WITH TMP.CUST_ID = '10001009208' CONNECT BY TMP.PARENT_CUST_ID = PRIOR TMP.CUST_ID ) union all select distinct OB.BUSI_ORDER_ID,OB.HIS_ID, OB.BUSI_CODE, OB.CUST_ID, OB.CEASE_REASON, OB.ORDER_STATE, OB.CHANNEL_TYPE, OB.USER_ID, OB.IS_BATCH_ORDER, OB.APPLICATION_ID, OB.CREATE_DATE, OB.DONE_DATE, OB.EFF_DATE, OB.EXP_DATE, OB.OPER_ID, OB.ORG_ID, OB.REGION_ID, OB.NOTE, OB.PROCESS_STATE, nvl(oi.cust_name,ic.cust_name) cust_name , nvl(oc.icc_id, iu.icc_id) icc_id, nvl(oc.svc_num,iu.svc_num) svc_num, icp.cust_name parent_cust_name, icp.cust_id parent_cust_id, ol.order_list_id from ord_busi_his ob left join ord_offer_his oo on oo.busi_order_id = ob.busi_order_id 优化一下

可以考虑以下优化方式：

1. 使用INNER JOIN代替LEFT JOIN：如果确保两个表中都含有匹配的行，则使用INNER JOIN可以提高查询效率。

2. 使用EXISTS代替IN：EXISTS执行速度比IN更快，因为它只需要找到匹配的第一个结果，而不是找到所有匹配的结果。

3. 简化子查询：在查询中可以尝试简化子查询，以减少查询的复杂度。

4. 使用索引：使用索引可以提高查询效率，可以根据查询中经常使用的列添加索引。

5. 避免使用SELECT *：只查询需要的列，避免使用SELECT *可以减少查询的复杂度，提高查询效率。

编写存储过程 SELECT a.order_id, a.done_date, a.cust_id, a.subscriber_ins_id, a.access_num, c.dev_id, c.dev_name, c.corp_org, c.company_name, c.department_code, c.department_name, c.remarks FROM JOUR1.Om_Subscriber_202301 a LEFT JOIN JOUR1.om_order_202301 b ON a.order_id = b.order_id LEFT JOIN params1.sec_developer c ON b.dev_id = c.dev_id UNION ALL SELECT a.order_id, a.done_date, a.cust_id, a.subscriber_ins_id, a.access_num, c.dev_id, c.dev_name, c.corp_org, c.company_name, c.department_code, c.department_name, c.remarks FROM JOUR1.Om_Subscriber_202302 a LEFT JOIN JOUR1.om_order_202302 b ON a.order_id = b.order_id LEFT JOIN params1.sec_developer c ON b.dev_id = c.dev_id UNION ALL SELECT a.order_id, a.done_date, a.cust_id, a.subscriber_ins_id, a.access_num, c.dev_id, c.dev_name, c.corp_org, c.company_name, c.department_code, c.department_name, c.remarks FROM JOUR1.Om_Subscriber_202303 a LEFT JOIN JOUR1.om_order_202303 b ON a.order_id = b.order_id LEFT JOIN params1.sec_developer c ON b.dev_id = c.dev_id UNION ALL SELECT a.order_id, a.done_date, a.cust_id, a.subscriber_ins_id, a.access_num, c.dev_id, c.dev_name, c.corp_org, c.company_name, c.department_code, c.department_name, c.remarks FROM JOUR1.Om_Subscriber_202304 a LEFT JOIN JOUR1.om_order_202304 b ON a.order_id = b.order_id LEFT JOIN params1.sec_developer c ON b.dev_id = c.dev_id

你可以编写一个存储过程来执行这个查询。下面是一个示例：

CREATE OR REPLACE PROCEDURE get_data AS
BEGIN
  -- 创建临时表来保存结果
  CREATE GLOBAL TEMPORARY TABLE temp_data (
    order_id          NUMBER,
    done_date         DATE,
    cust_id           NUMBER,
    subscriber_ins_id NUMBER,
    access_num        VARCHAR2(100),
    dev_id            NUMBER,
    dev_name          VARCHAR2(100),
    corp_org          VARCHAR2(100),
    company_name      VARCHAR2(100),
    department_code   VARCHAR2(100),
    department_name   VARCHAR2(100),
    remarks           VARCHAR2(100)
  ) ON COMMIT PRESERVE ROWS;

  -- 第一个查询
  INSERT INTO temp_data
  SELECT a.order_id,
         a.done_date,
         a.cust_id,
         a.subscriber_ins_id,
         a.access_num,
         c.dev_id,
         c.dev_name,
         c.corp_org,
         c.company_name,
         c.department_code,
         c.department_name,
         c.remarks
  FROM JOUR1.Om_Subscriber_202301 a
  LEFT JOIN JOUR1.om_order_202301 b
    ON a.order_id = b.order_id
  LEFT JOIN params1.sec_developer c
    ON b.dev_id = c.dev_id;

  -- 后续查询使用UNION ALL连接
  INSERT INTO temp_data
  SELECT a.order_id,
         a.done_date,
         a.cust_id,
         a.subscriber_ins_id,
         a.access_num,
         c.dev_id,
         c.dev_name,
         c.corp_org,
         c.company_name,
         c.department_code,
         c.department_name,
         c.remarks
  FROM JOUR1.Om_Subscriber_202302 a
  LEFT JOIN JOUR1.om_order_202302 b
    ON a.order_id = b.order_id
  LEFT JOIN params1.sec_developer c
    ON b.dev_id = c.dev_id;

  INSERT INTO temp_data
  SELECT a.order_id,
         a.done_date,
         a.cust_id,
         a.subscriber_ins_id,
         a.access_num,
         c.dev_id,
         c.dev_name,
         c.corp_org,
         c.company_name,
         c.department_code,
         c.department_name,
         c.remarks
  FROM JOUR1.Om_Subscriber_202303 a
  LEFT JOIN JOUR1.om_order_202303 b
    ON a.order_id = b.order_id
  LEFT JOIN params1.sec_developer c
    ON b.dev_id = c.dev_id;

  INSERT INTO temp_data
  SELECT a.order_id,
         a.done_date,
         a.cust_id,
         a.subscriber_ins_id,
         a.access_num,
         c.dev_id,
         c.dev_name,
         c.corp_org,
         c.company_name,
         c.department_code,
         c.department_name,
         c.remarks
  FROM JOUR1.Om_Subscriber_202304 a
  LEFT JOIN JOUR1.om_order_202304 b
    ON a.order_id = b.order_id
  LEFT JOIN params1.sec_developer c
    ON b.dev_id = c.dev_id;

  -- 查询结果
  SELECT * FROM temp_data;

  -- 删除临时表
  DROP TABLE temp_data;
END;
/

这个存储过程创建了一个临时表 `temp_data` 来保存查询结果，并将每个查询的结果插入到临时表中。最后，通过查询 `temp_data` 表来获取结果。

请注意，根据你的实际需求和数据库结构，你可能需要修改表和列的定义，以及查询的逻辑。确保在执行存储过程之前，已经创建了所需的表和索引。