C语言调用存储过程并且获得返回值
作者：刘晨晖
1. 数据库名：test ；
表名：chengjibiao;
字段：Id int , Name char , English int , Maths int , Physis int ;
2. 存储过程：
DELIMITER $$
DROP PROCEDURE IF EXISTS `test`.`query` $$
CREATE DEFINER=`root`@`localhost` PROCEDURE `query`( in N int, out s char(254) )
BEGIN
declare a,b,c,d,e int;
declare f char(100);
declare g decimal(4,2);
set e=1;
drop table if exists zongping;
create table zongping(NUM int,Name char(255),English int,Maths int,Physis int,Total int,aver decimal(4,2));
repeat
select English,Maths,Physis,Name into a,b,c,f from chengjibiao where Id=e;
set d=a+b+c;
set g=(a+b+c)/3;
insert into zongping(NUM,Name,English,Maths,Physis,Total,aver) values( e,f,a,b,c,d,g );
set e=e+1;
until e=N
end repeat;
select *from zongping as s;
drop table zongping;
END $$
DELIMITER ;
3. 主函数（在文件main.c 中）：
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "/usr/include/mysql/mysql.h"
#include "/usr/include/mysql/mysql_version.h"
#include "/usr/include/mysql/errmsg.h"
int main( int argc,char **argv[] )
{
MYSQL mysql;
MYSQL_ROW results,record;
char query[50],s[254];
/** 链接数据库 **/
if(!mysql_init(&mysql))
{
printf("mysql_init failed!/n");
return 0;
}
if(!mysql_real_connect(&mysql,"localhost","root","123456","test",0,NULL,CLIENT_MULTI_STATEMENTS))
{
printf("mysql_real_connect() failed!/n");
mysql_close(&mysql);
return 0;
}
/** 调用存储过程 **/
strcpy(query,"call query(7,@s)");
mysql_real_query(&mysql,query,(unsigned int)strlen(query));
/** 取得存储过程返回值 **/
mysql_query(&mysql, "SELECT @s ");
results = mysql_store_result(&mysql);
/** 输出返回值 **/
printf( "Id Name Maths English Physis Total aver/n" );
while((record = mysql_fetch_row(results)))
{
printf("%1s%10s%8s%12s%11s%10s%10s/n", record[0], record[1],record[2],record[3],record[4],record[5],record[6]);
}
mysql_free_result(results);
mysql_close(&mysql);
return 0;
}
（编译：gcc -o main main.c -L/usr/lib/mysql/ -lmysqlclient -lz ）
4.
成绩表：
+----+-------+-------+---------+--------+
| Id | Name | Maths | English | Physis |
+----+-------+-------+---------+--------+
| 1 | liu | 90 | 80 | 86 |
| 2 | zhang | 88 | 86 | 87 |
| 3 | xiao | 78 | 88 | 98 |
| 4 | wang | 77 | 87 | 97 |
| 5 | li | 79 | 89 | 99 |
| 6 | yi | 67 | 77 | 87 |
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运行程序得到的结果：
Id Name Maths English Physis Total aver
1 liu 90 80 86 256 85.33
2 zhang 88 86 87 261 87.00
3 xiao 78 88 98 264 88.00
4 wang 77 87 97 261 87.00
5 li 79 89 99 267 89.00
6 yi 67 77 87 231 77.00