網上的都是一些靜態的，用CASE WHEN結構實現。所以我寫了一個動態的。




SP 代碼：

DELIMITER $$

DROP PROCEDURE IF EXISTS `test`.`sp_row_column_wrap`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `sp_row_column_wrap`(IN $schema_name varchar(64),
IN $table_name varchar(64))
BEGIN
??declare cnt int(11);
??declare $table_rows int(11);
??declare i int(11);
??declare j int(11);
??declare s int(11);
??declare str varchar(255);
??-- Get the column number of the table
??select count(1) from information_schema.columns where table_schema=$schema_name and table_name=$table_name into cnt;
??-- Get the row number of the table
??select table_rows from information_schema.tables where table_schema = $schema_name and table_name=$table_name into $table_rows;
??-- Check whether the table exists or not
??drop table if exists test.temp;
??create table if not exists test.temp (`1` varchar(255) not null);
??-- loop1 start
??set i = 0;
??loop1:loop
????if i = $table_rows-1 then
??????leave loop1;
????end if;
????set @stmt1 = concat('alter table test.temp add `',i+2,'` varchar(255) not null');
????prepare s1 from @stmt1;
????execute s1;
????deallocate prepare s1;
??? set @stmt1 = '';
????set i = i + 1;
??end loop loop1;
??-- loop1 end;
??set s = 0;
??-- loop2 start
??loop2:loop
??-- leave loop2
????if s=cnt then
??????leave loop2;
????end if;
????set @stmt2 = concat('select column_name from information_schema.columns where table_schema="',$schema_name,
????????????????????????'" and table_name="',$table_name,'" limit ',s,',1 into @temp;');
????prepare s2 from @stmt2;
????execute s2;
????deallocate prepare s2;
??? set @stmt2 = '';
????set j=0;
????set str = ' select ';
????-- Loop3 start
????loop3:loop
??????if j = $table_rows then
????????leave loop3;
??????end if;
??????set @stmt3 = concat('select ',@temp,' from ',$schema_name,'.',$table_name,' limit ',j,',1 into @temp2;');
??????prepare s3 from @stmt3;
??????execute s3;
??????set str = concat(str,'"',@temp2,'"',',');
??????deallocate prepare s3;
????? set @stmt3 = '';
??????set j = j+1;
????end loop loop3;
????set str = left(str,length(str)-1);
????-- insert new data into table
????set @stmt4 = concat('insert into test.temp',str,';');
????prepare s4 from @stmt4;
????execute s4;
????deallocate prepare s4;
??? set @stmt4 = '';
????set s=s+1;
??end loop loop2;
END$$

DELIMITER ;



以下是測試結果：
======
select * from a;
select * from b;
select * from salary;

call sp_row_column_wrap('test','a');
select * from test.temp;
call sp_row_column_wrap('test','b');
select * from test.temp;
call sp_row_column_wrap('test','salary');
select * from test.temp;

query result(2 records)

aid	title
1	111
2	222

query result(3 records)

bid	aid	image	time
1	2	1.gif	2007-08-08
2	2	2.gif	2007-08-09
3	2	3.gif	2007-08-08

query result(7 records)

id	cost	des	Autoid
1	10	aaaa	1
1	15	bbbb	2
1	20	cccc	3
2	80	aaaa	4
2	100	bbbb	5
2	60	dddd	6
3	500	dddd	7

query result(2 records)

1	2
1	2
111	222

query result(4 records)

1	2	3
1	2	3
2	2	2
1.gif	2.gif	3.gif
2007-08-08	2007-08-09	2007-08-08

query result(4 records)

1	2	3	4	5	6	7
1	1	1	2	2	2	3
10	15	20	80	100	60	500
aaaa	bbbb	cccc	aaaa	bbbb	dddd	dddd
1	2	3	4	5	6	7

?

轉載于:https://www.cnblogs.com/secbook/archive/2008/04/19/2655306.html

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