Database

ssql := s_SEL||s_FROM1||s_WHERE||s_WH_PER||s_WH_CC||s_WH_VEN
||s_UNION||
           s_SEL||s_FROM2||s_WHERE||s_WH_PER||s_WH_CC||s_WH_VEN

execute immediate ssql

int ThreadExeSQL(MYSQL* lpSQLConn, char * sql, int iLen)
{

    if (mysql_real_query(lpSQLConn, sql, iLen))
    {
        MYSQL_RES* lpGetSQLRes = mysql_store_result(lpSQLConn);
        mysql_free_result(lpGetSQLRes);
        return -1;
    }

    //mysql_errno(lpSQLConn);
    //mysql_error(lpSQLConn);

    MYSQL_RES* lpGetSQLRes = mysql_store_result(lpSQLConn);
    mysql_free_result(lpGetSQLRes); // release sql memory

    return 0; // success
}

void* ThreadSQL_HexWrite(void* lpGet)
{

    LPThreadParam getParam = (LPThreadParam)lpGet;

    MYSQL* lpSQLConn = (MYSQL*)&getParam->lpSQLConn;
    int iThreadIdx = getParam->iThreadIdx;

    printf("ID:%d\n", iThreadIdx);

    mysql_thread_init();

    lpSQLConn = mysql_init(NULL);


    if (!mysql_real_connect(lpSQLConn, g_host_name, g_user_name, g_password, g_db_name, g_db_port, NULL, 0))
    {
        ThreadSQLError(lpSQLConn, NULL);
        return;
    }
    else
    {
        printf("mysql_real_connect OK!\n");
    }


    for (int i = 0; i < 1000000; i++)
    {

        char lpCmdStr[8192] = "\0";
        sprintf(lpCmdStr, "update %s set %s=0x%d where id=%d\0", "tb_Data", "Info", i, 1);

        if (ThreadExeSQL(lpSQLConn, (char*)lpCmdStr, strlen(lpCmdStr)))
        {
            MySQLError getError = ThreadSQLError(lpSQLConn, NULL);
            HandleMySqlError(getError);

            continue; //erroe
        }
        else
        {
            printf("ok. ");
        }

        usleep(1000 * 10);
    }

    mysql_close(lpSQLConn);

    mysql_thread_end();


    printf("ThreadSQL_HexWrite OK!\n");
}


MYSQL* g_MySQLConnList[100];

void main()
{

    if (mysql_library_init(0, NULL, NULL))
    {
        printf("could not initialize MySQL client library\n");
        exit(1);
    }


    int thread_num = 1;

    //while (true)
    {
        pthread_t *pTh = new pthread_t[thread_num];


        for (int i = 0; i < thread_num; i++)
        {

            LPThreadParam lpSetParam = new ThreadParam;
            lpSetParam->lpSQLConn = (MYSQL*)&g_MySQLConnList[i];
            lpSetParam->iThreadIdx = i;

            printf("---create thread idx:%d\n", i);
            if (0 != pthread_create(&pTh[i], NULL, ThreadSQL_HexWrite, lpSetParam))
            {
                printf("pthread_create failed\n");
                continue;
            }
        }

        for (int i = 0; i < thread_num; i++)
        {
            pthread_join(pTh[i], NULL);
        }

        delete[] pTh;
    }

    mysql_library_end();

    printf("All Done!\n");

}

DECLARE
        @LastID int = 0,
        @NextID int,
        @RC int = 1;
    
WHILE (@RC > 0)
BEGIN
    SELECT  TOP 5000
            @NextID = s.id
    FROM    Source s
    WHERE   s.id> @LastID
    ORDER BY s.id
    ;
    UPDATE  t
        SET  ------
    FROM    Source s
    JOIN    Target t ON t.id = s.id
    WHERE   s.id > @LastID 
        AND s.id <= @NextID 
    ;
    SET @RC = @@ROWCOUNT;
    SET @LastID = @NextID ;
END