mysql存儲過程（清洗因業務變動遺留下來的無關數據）

舊業務需求：一個客戶能夠被同一個公司下的不一樣用戶屢次新建。

新業務需求：一個客戶能夠被同一個公司下的用戶新建一次。

清洗舊業務遺留下來的數據，清洗規則：誰先建立客戶誰保留，後面建立的通通標記爲無用狀態。

DELIMITER $$
CREATE PROCEDURE deletechongfu()
BEGIN
DECLARE org_id INT(11);
DECLARE count_num INT;
DECLARE customer_code VARCHAR(32);
DECLARE customer_id VARCHAR(255);
-- 遍歷數據結束標誌
DECLARE done INT DEFAULT FALSE;
DECLARE customerCursor CURSOR FOR SELECT t1.id,t1.code,t1.org_id,COUNT(*) AS COUNT FROM (SELECT t.id,t.org_id,t.name,t.code,tc.tuser_id,tc.create_time FROM credit.hd_tuser_customer tc INNER JOIN (SELECT t.code,t.name,t.org_id,t.id FROM credit.hd_customer_user t WHERE t.status = '1') t ON tc.customer_id = t.id WHERE tc.status = '1') t1 GROUP BY t1.code,t1.org_id HAVING COUNT >1;
-- 將結束標誌綁定到遊標
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

OPEN customerCursor;
-- 開始循環
read_loop: LOOP
-- 提取遊標裏的數據，這裏只有一個，多個的話也同樣；
FETCH customerCursor INTO customer_id,customer_code,org_id,count_num;
SET @count_total = 0;
SELECT customer_id INTO @customer_id;
SELECT (count_num-1) INTO @count_total;
PREPARE s1 FROM 'update credit.hd_tuser_customer set status = "0" where (customer_id,tuser_id) in (SELECT tt.customer_id,tt.tuser_id FROM (select t.customer_id,t.tuser_id from credit.hd_tuser_customer t where t.customer_id = ? and t.status = "1" order by t.create_time asc limit 0,?) tt)';
EXECUTE s1 USING @customer_id,@count_total;
-- 聲明結束的時候
IF done THEN
LEAVE read_loop;
END IF;
END LOOP;
-- 關閉遊標
CLOSE customerCursor;
END$$
DELIMITER ;

 

在寫存儲過程的途中，遇到如下問題：

1：EXECUTE s1 USING @customer_id,@count_total 這裏只能是使用用戶變量。

2：在編寫預處理語句的時候，用問號？來標記佔位符。要謹記該佔位符問號不能加引號或雙引號，即便與字符串鏈接。

3：子查詢不支持limit條件限制，解決方法是在該處子查詢外面再包一層子查詢。