ODBC:如何在c++中将空字符串绑定到null

#include <iostream>
#include <sql.h>
#include <sqlext.h>

int main() {
    SQLHENV env;
    SQLHDBC dbc;
    SQLHSTMT stmt;
    SQLRETURN ret;

    // 创建环境句柄
    ret = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &env);
    ret = SQLSetEnvAttr(env, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0);

    // 创建连接句柄
    ret = SQLAllocHandle(SQL_HANDLE_DBC, env, &dbc);
    ret = SQLDriverConnect(dbc, NULL, (SQLCHAR*)"DRIVER={ODBC Driver};SERVER=localhost;DATABASE=mydb;UID=username;PWD=password;", SQL_NTS, NULL, 0, NULL, SQL_DRIVER_COMPLETE);

    // 创建语句句柄
    ret = SQLAllocHandle(SQL_HANDLE_STMT, dbc, &stmt);

    // 绑定参数
    SQLCHAR paramValue[SQL_NULL_DATA];
    SQLLEN paramLength = SQL_NULL_DATA;
    ret = SQLBindParameter(stmt, 1, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_CHAR, 0, 0, paramValue, sizeof(paramValue), &paramLength);

    // 设置参数值为空字符串
    paramValue[0] = '\0';
    paramLength = SQL_NTS;

    // 执行SQL语句
    ret = SQLExecDirect(stmt, (SQLCHAR*)"INSERT INTO mytable (column) VALUES (?)", SQL_NTS);

    // 释放资源
    ret = SQLFreeHandle(SQL_HANDLE_STMT, stmt);
    ret = SQLDisconnect(dbc);
    ret = SQLFreeHandle(SQL_HANDLE_DBC, dbc);
    ret = SQLFreeHandle(SQL_HANDLE_ENV, env);

    return 0;
}