动态嵌套游标解决方案

Posted 2020-08-31 Kevin-kw

1.业务说明：t_user表中存储着原始数据表，业务需要将这些表中存储的数据转移到ibms_equipmentbasedata_minute表中。

2.表结构：

　　2.1存储表名称

1 CREATE TABLE `t_user` (
2 `id` varchar(40) NOT NULL,
3 PRIMARY KEY (`id`)
4 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

      2.2目标表

 1 CREATE TABLE `ibms_equipmentbasedata_minute` (
 2 `id` bigint(20) NOT NULL AUTO_INCREMENT,
 3 `created_by` varchar(255) DEFAULT NULL,
 4 `created_date` datetime DEFAULT NULL,
 5 `data_damage` varchar(255) DEFAULT NULL,
 6 `energysid` int(11) DEFAULT NULL,
 7 `is_health` int(11) DEFAULT NULL,
 8 `meter_type` int(11) DEFAULT NULL,
 9 `posid` int(11) DEFAULT NULL,
10 `pro_code` varchar(255) DEFAULT NULL,
11 `timestamp` datetime DEFAULT NULL,
12 `value` double DEFAULT NULL,
13 `equid` varchar(255) DEFAULT NULL,
14 PRIMARY KEY (`id`)
15 ) ENGINE=InnoDB AUTO_INCREMENT=2730 DEFAULT CHARSET=utf8;

       2.3 t_user存储的表

 1 CREATE TABLE `sgly_11011500010010010_01` (
 2 `ID` int(11) NOT NULL AUTO_INCREMENT,
 3 `timestamp` datetime DEFAULT NULL,
 4 `trendFlags` int(11) DEFAULT NULL,
 5 `status` int(11) DEFAULT NULL,
 6 `value` double DEFAULT NULL,
 7 `TRENDFLAGS_TAG` varchar(500) DEFAULT NULL,
 8 `STATUS_TAG` varchar(500) DEFAULT NULL,
 9 `created_by` varchar(30) DEFAULT NULL,
10 `created_date` datetime DEFAULT NULL,
11 `trend_flags` int(11) DEFAULT NULL,
12 PRIMARY KEY (`ID`)
13 ) ENGINE=InnoDB AUTO_INCREMENT=1810 DEFAULT CHARSET=utf8;

3.存储过程

 1 delimiter $$
 2 drop procedure if exists p_simulate_dynamic_cursor;
 3 create procedure p_simulate_dynamic_cursor()
 4 begin
 5 declare v_sql varchar(4000);
 6 
 7 declare v_field varchar(4000);
 8 
 9 declare v_result varchar(4000) default ‘‘;
10 
11 declare cur_temp cursor for 
12 select v.* from view_temp_20150701 v;
13 declare continue handler for not found set v_field = null;
14 set v_sql = ‘create view view_temp_20150701 as select t.id from t_user t‘;
15 set @v_sql = v_sql;
16 prepare statement from @v_sql;
17 execute statement;
18 deallocate prepare statement;
19 open cur_temp;
20 fetch cur_temp into v_field;
21 
22 while(v_field is not null) do
23 -- declare cur_table_data cursor for select d.* from view_temp_data d;
24 -- set v_result = concat(v_result, v_field, ‘,‘);
25 CALL p2_simulate_dynamic_cursor(v_field);
26 fetch cur_temp into v_field;
27 end while;
28 close cur_temp;
29 
30 drop view if exists view_temp_20150701;
31 end;
32 $$
33 delimiter ;
34 -- call p_simulate_dynamic_cursor();
35 
36 -- ----------------------------另一个存储过程动态游标-------------------------------------
37 delimiter $$
38 drop procedure if exists p2_simulate_dynamic_cursor;
39 
40 create procedure p2_simulate_dynamic_cursor(IN tableName varchar(4000))
41 begin
42 DECLARE done INT DEFAULT 0;
43 DECLARE equiName VARCHAR(400);
44 declare v_sql varchar(4000);
45 declare v_time TIMESTAMP;
46 declare v_value DOUBLE;
47 declare v_result varchar(4000) default ‘‘;
48 declare cur_temp cursor for select timestamp,value from view_temp_data;
49 DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
50 SET equiName=SUBSTR(tableName,6,17);
51 set v_sql = concat(‘create view view_temp_data as select timestamp,value from ‘ ,tableName);
52 
53 
54 set @v_sql = v_sql;
55 prepare statement from @v_sql;
56 
57 execute statement;
58 deallocate prepare statement;
59 
60 open cur_temp;
61 fetch cur_temp into v_time,v_value;
62 while (done=0) do
63 INSERT INTO ibms_equipmentbasedata_minute(timestamp,value,equid) VALUES(v_time,v_value,equiName);
64 set v_result = concat(v_result,v_time, v_value, ‘,‘);
65 fetch cur_temp into v_time,v_value;
66 end while;
67 close cur_temp;
68 select v_result;
69 
70 drop view if exists view_temp_data;
71 end;
72 $$
73 delimiter ;

4.注意事项：解决方式主要是用另一个存储过程来存储另一个嵌套的游标。