用存储过程 拆分字段,该怎么处理

用存储过程 拆分字段

原表数据:

C1 C2

— ————–

1 aa,bbb,cccc,ddd

2 eee,fff,gggg,hhhh

转化成格式

C1 c2

— ———-

1 aa

1 bbb

1 cccc

1 ddd

2 eee

2 fff

2 gggg

2 hhhh

数据量很大，写一个存储过程实现上述的转化，怎么写效率高一点

直接用SQL语句+辅助表不行吗？




可以把原表的c2字段通过一些处理拼成一条批量插入的sql，再动态执行

SQL code

select replace(concat('insert into t2 values(@id,\'',replace(c2,',','\'),(@id,\''),'\')'),'@id',c1) from t1;


推测楼主想要这样一个函数。居家旅行常备无患。


  
  

   
   SQL code
   
   
mysql> DELIMITER $$
mysql> DROP PROCEDURE IF EXISTS `split`$$
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> CREATE PROCEDURE `split`(
    ->     str VARCHAR(9999),
    ->     sep CHAR(1)
    -> )
    -> BEGIN
    ->     DECLARE strlen INT;
    ->     DECLARE last_index INT;
    ->     DECLARE cur_index INT;
    ->     DECLARE cur_char VARCHAR(200);
    ->     DECLARE len INT;
    ->     SET cur_index=1;
    ->     SET last_index=0;
    ->     SET strlen=LENGTH(str);
    ->     DROP TABLE IF EXISTS tmp_tb_split;
    ->     CREATE TEMPORARY TABLE tmp_tb_split(
    ->         id INT AUTO_INCREMENT,
    ->         VALUE VARCHAR(20),
    ->         PRIMARY KEY (`ID`),
    ->         UNIQUE KEY `ID` (`ID`)
    ->     ) ;
    ->     WHILE(cur_index<=strlen) DO
    ->     BEGIN
    ->         IF SUBSTRING(str FROM cur_index FOR 1)=sep OR cur_index=strlen TH
EN
    ->             SET len=cur_index-last_index-1;
    ->             IF cur_index=strlen THEN
    ->                SET len=len+1;
    ->             END IF;
    ->             INSERT INTO tmp_tb_split(`value`)VALUES(SUBSTRING(str FROM (l
ast_index+1) FOR len));
    ->             SET last_index=cur_index;
    ->         END IF;
    ->         SET cur_index=cur_index+1;
    ->     END;
    ->     END WHILE;
    ->
    ->     SELECT * FROM tmp_tb_split;
    -> END$$
Query OK, 0 rows affected (0.01 sec)

mysql> DELIMITER ;
mysql> CALL split('a,b,c',',');
+----+-------+
| id | VALUE |
+----+-------+
|  1 | a     |
|  2 | b     |
|  3 | c     |
+----+-------+
3 rows in set (0.23 sec)

Query OK, 0 rows affected, 1 warning (0.23 sec)

mysql>
mysql>
mysql> DELIMITER $$
mysql>
mysql> DROP PROCEDURE IF EXISTS `split`$$
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> CREATE PROCEDURE `split`(
    ->     str VARCHAR(9999),
    ->     sep CHAR(1)
    -> )
    -> BEGIN
    ->     DECLARE strlen INT;
    ->     DECLARE last_index INT;
    ->     DECLARE cur_index INT;
    ->     DECLARE cur_char VARCHAR(200);
    ->     DECLARE len INT;
    ->     SET cur_index=1;
    ->     SET last_index=0;
    ->     SET strlen=LENGTH(str);
    ->     DROP TABLE IF EXISTS tmp_tb_split;
    ->     CREATE TEMPORARY TABLE tmp_tb_split(
    ->         id INT AUTO_INCREMENT,
    ->         VALUE VARCHAR(20),
    ->         PRIMARY KEY (`ID`),
    ->         UNIQUE KEY `ID` (`ID`)
    ->     ) ;
    ->     WHILE(cur_index<=strlen) DO
    ->     BEGIN
    ->         IF SUBSTRING(str FROM cur_index FOR 1)=sep OR cur_index=strlen TH
EN
    ->             SET len=cur_index-last_index-1;
    ->             IF cur_index=strlen THEN
    ->                SET len=len+1;
    ->             END IF;
    ->             INSERT INTO tmp_tb_split(`value`)VALUES(SUBSTRING(str FROM (l
ast_index+1) FOR len));
    ->             SET last_index=cur_index;
    ->         END IF;
    ->         SET cur_index=cur_index+1;
    ->     END;
    ->     END WHILE