c/c++-使用 mysql c api 中，预处理查询条件 当过滤字段是字符串时

mysqlc/c++

<code>#include <stdio.h>#include <mysql>#include <string.h>int main(void){    // declares    MYSQL * connection = NULL;    MYSQL_STMT * stmt = NULL;    MYSQL_BIND bind[3];    MYSQL_BIND inbind;    // preprocess    bzero(bind, sizeof(bind));    bzero(&inbind, sizeof(inbind));    // declare MYSQL * ptr    connection = mysql_init(NULL);    if (NULL == connection)    {        fprintf(stderr, "mysql_init err!");        return -1;    }    // connect    connection = mysql_real_connect(connection, "localhost", "root", "root", "dblinuxcmysqlctr", 0, NULL, 0);    if (NULL == connection)    {        fprintf(stderr, "mysql_real_connect err!");        return -1;    }    /* 1. init */    stmt = mysql_stmt_init(connection);    /*   ********************************************************       */    //char * insertsql = "select name from tlinuxcmysqlctr where age = ?;";  // 这里不就可以过滤了，过滤出来没有数据，是为啥呀？    char * insertsql = "select name from tlinuxcmysqlctr where name = ?;";    /*   ********************************************************       */    /* 2. prepare */    if(mysql_stmt_prepare(stmt, insertsql, strlen(insertsql)))    {        printf("mysql_stmt_prepare err!\n");        return -1;    }    char inpara1[50] = {0};    //int inpara1 = 4;    char outpara1[50] = {0};    //bind[0].buffer_type = MYSQL_TYPE_LONG;    //bind[0].buffer = &inpara1;    //bind[0].buffer_length = sizeof(inpara1);    bind[0].buffer_type = MYSQL_TYPE_STRING;    strcpy(inpara1, "hello");    bind[0].buffer = inpara1;    bind[0].buffer_length = sizeof(inpara1);    bind[1].buffer_type = MYSQL_TYPE_STRING;    bind[1].buffer = outpara1;    bind[1].buffer_length = 50;    /* 3. bind_param */    mysql_stmt_bind_param(stmt, bind + 0);    /* 4. execute */    if (mysql_stmt_execute(stmt))    {        printf("sorry\n");    }    else    {        /* 3.5 */        mysql_stmt_bind_result(stmt, bind + 1);        printf("bind[0].buffer = %s\n", (char *)bind[0].buffer);        if (0 != mysql_stmt_store_result(stmt))        {            printf("store result stmt err\n");            return -1;        }        else        {            printf("----------------------------table data--------------------------------\n");            while (!mysql_stmt_fetch(stmt))            {                printf("name = %s\n", outpara1);            }        }        mysql_stmt_free_result(stmt);    }    /* 5. close */    mysql_stmt_close(stmt);    // mysql_close    mysql_close(connection);    return 0;}</string.h></mysql></stdio.h></code>