在MySQL数据库中使用C执行SQL语句

int mysql_query(mysql *connection, const char *query)

my_ulonglong mysql_affected_rows(mysql *connection);

#include #include #include "mysql.h"int main(int argc, char *argv[]) {mysql my_connection;int res;mysql_init(&my_connection); if (mysql_real_connect(&my_connection, "localhost",     "rick", "bar", "rick", 0, null, 0)) {    printf("connection success/n");   res = mysql_query(&my_connection,          "insert into children(fname,age),          values('ann',3)");   if (!res) {              printf("inserted %lu rows/n",               (unsigned long)mysql_affected_rows(&my_connection));            } else {              fprintf(stderr, "insert error %d: s/n",mysql_errno ,              (&my_connection),              mysql_error(&my_connection));             }    mysql_close(&my_connection);         } else {           fprintf(stderr, "connection failed/n");            if (mysql_errno(&my_connection)) {fprintf(stderr, "connection error %d: %s/n",mysql_errno(&my_connection),mysql_error(&my_connection));            }         }         return exit_success;    }

 mysql_errno(&my_connection), mysql_error(&my_connection));         }      }      res = mysql_query(&my_connection, "update children set age = 4      where fname = 'ann'");      if (!res) {         printf("updated %lu rows/n",                           (unsigned long)mysql_affected_rows(&my_connection));      } else {        fprintf(stderr, "update error %d: %s/n",mysql_errno(&my_connection),                                                  mysql_error(&my_connection));      }

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if (mysql_real_connect(&my_connection, "localhost",                                  "rick", "bar", "rick", 0, null, client_found_rows)) {

如果我们在数据库中复位数据，然后运行带有这种修改的程序，则它报告的行数为4。

函数mysql_affected_rows还有最后一个奇怪之处，它发生在从数据库中删除数据时。如果使用where子句，则mysql_affected_rows将按预期返回删除行数。但是，如果没有where子句，则删除所有行，报告受影响的行数却为0。这是因为由于效率原因优化删除整个表。这种行为不受client_found_rows选项标志的影响。