1. Makefile

INCLUDE=/usr/include/mysql/

LIBS=/usr/lib/mysql

all:

gcc -I$(INCLUDE) -L$(LIBS) -lmysqlclient xxx.c -o xxx

clean:

rm -f xxx

2. mysql的头文件和库文件配置

如果mysql是默认安装的，在Makefile里配置

INCLUDE=/usr/include/mysql

LIBS=/usr/lib/mysql

如果mysql是安装到/usr/local/mysql，在Makefile里配置

INCLUDE=/usr/local/mysql/include/mysql

LIBS=/usr/local/mysql/lib/mysql

如果mysql在/usr/local/mysql目录，还需要添加一条链接，否则可能出现 “libmysqlclient.so.16: cannot open shared object file: No such file or directory”

ln -s /usr/local/mysql/lib/mysql/libmysqlclient.so.16 /usr/lib/libmysqlclient.so.16

3. Unknown column 'opcode' in 'where clause'

检查sql语句是否写的有误。

4. Commands out of sync; you can't run this command now

如果你在你的客户代码中得到Commands out of sync; You can't run this command now，你正在以错误的次序调用客户函数

我在代码里为了获取结果的行数，使用如下语句报的这个错误

mysql_real_query(mysql, sql, strlen(sql));

num = mysql_affected_rows(mysql);

后来我把语句改成如下就可以了

mysql_real_query(mysql, sql, strlen(sql));

rs = mysql_store_result(mysql);

num = mysql_num_rows(rs);

5. Mysql将查询结果放到另一张表里

首先得建好另一张表，然后

insert into new_table select xxx,xxx,xxx from old_table where xxx;

6. 取查询结果

MYSQL *mysql;

MYSQL_RES *rs;

MYSQL_ROW row;

char *sql = "select uid, uname from users where uid=xxx";

mysql_real_connect(mysql, sql, strlen(sql);

rs = mysql_store_result(mysql);

row = mysql_fetch_row(rs);

结果就存放在row中，row[0]，row[1]分别是uid，uname，可以使用

atoi或者atol将结果转化成整数。

7. 运行时出现“浮点数例外”www.2cto.com

出现这个是因为代码中有除0，检查代码对除数为0进行判断。