MySQL Stored procedure – Split Delimited string into Rows

By
Kedar
– December 5, 2009

This procedure will split  a “;” separated column in to new fields preserving ids.

This is very specific problem, lets check it with example.

Consider a sample table test:

source-table

And we want output as follows:

output-table

So again I wrote a procedure.

Procedure will read a data from “tmp” table and will split data by my_delimiter delimiter and generate a temporary table.

You may alter it as per requirement.

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Download Stored Procedure : split_string

DELIMITER $$


DROP PROCEDURE IF EXISTS `split_string` $$
CREATE DEFINER=`root`@`localhost` PROCEDURE `split_string`()
BEGIN

DECLARE my_delimiter CHAR(1);
DECLARE split_string varchar(255);
DECLARE done INT;
DECLARE occurance INT;
DECLARE i INT;
DECLARE split_id INT;
DECLARE ins_query VARCHAR(500);
DECLARE splitter_cur CURSOR FOR
SELECT id,cat from tmp;

DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;

DROP TEMPORARY TABLE IF EXISTS `my_splits`;
CREATE TEMPORARY TABLE `my_splits` (
`splitted_column` varchar(45) NOT NULL,
`id` int(10) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

OPEN splitter_cur;
splitter_loop:LOOP
FETCH splitter_cur INTO split_id,split_string;

SET my_delimiter=’;';
SET occurance=length(split_string)-length(replace(split_string,my_delimiter,”))+1;
IF done=1 THEN
LEAVE splitter_loop;
END IF;
#  select occurance;
IF occurance > 0 then
#select occurance;
set i=1;
while i <= occurance do
#        select concat(“SUBSTRING_INDEX(SUBSTRING_INDEX( ‘”,split_string ,”‘, ‘”,my_delimiter,”‘, “,i, “),’”,my_delimiter,”‘,-1);”);
SET ins_query=concat(“insert into my_splits(splitted_column,id) values(“, concat(“SUBSTRING_INDEX(SUBSTRING_INDEX( ‘”,split_string ,”‘, ‘”,my_delimiter,”‘, “,i, “),’”,my_delimiter,”‘,-1),”,split_id,”);”));
#    select ins_query;
set @ins_query=ins_query;
PREPARE ins_query from @ins_query;
EXECUTE ins_query;
set i=i+1;
end while;
ELSE
set ins_query=concat(“insert into my_splits(splitted_column,id) values(“,split_string,”‘,”,split_id,”);”);
set @ins_query=ins_query;
PREPARE ins_query from @ins_query;
EXECUTE ins_query;
END IF;
set occurance=0;
END LOOP;

CLOSE splitter_cur;

END $$

DELIMITER ;

Usage: call split_string();

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