MYSQL CONCATÎÊÌâ
Îʸö²Ë²ËµÄÎÊÌ⣬ÎÒÏë¸üÐÂÄÚÈÝÖ´ÐÐÓï¾äupdate table set name=concat(name,"fff")£»µ«ÊÇconcatº¯Êý˵Ã÷²ÎÊýΪNULLʱ½«·µ»ØNULL£¬¶øÎҵıíÖÐnameµÄÖµ¿ÉÄÜÊÇNULL£¬ËùÒÔÖ´ÐкónameµÄֵΪNULL£¬²¢²»ÊÇfff,ÇëÎÊÎÒ¸ÃÔõô°ì£¿
pdate table set name=concat(COALESCE(name,''),"fff")
update table set name=concat(ifnull(name,''),"fff")
¼Ó¸öIFNULLÅжÏÒ»ÏÂNAMEÊÇ·ñΪ¿Õ
SQL code:
update table set name=concat(IFNULL(name,''),'fff');
SQL code:
mysql> select concat(IFNULL(null,''),'fff');
+-------------------------------+
| concat(IFNULL(null,''),'fff') |
+-------------------------------+
| fff |
+-------------------------------+
1 row in set (0.08 sec)
mysql>
·Ç³£¸Ðл¸÷λ´ïÈË
Ïà¹ØÎÊ´ð£º
ÎÒÊÇÓÃmysql×Ô´øµÄC API
if(mysql_real_connect(&mysql,"125.0.0.108","root","root","home",3306,NULL,0))
{
AfxMessageBox("Êý¾Ý¿âÁ¬½Óʧ°Ü") ......
ÎÒÒÔǰ°²×°ÁËÒ»´Î£¬ºóÀ´Ð¶ÔØÁË£¬ÏÖÔÚÔÙ°²×°µÄʱºò£¬Ìáʾ´íÎó£ºError 1305.Error reading from file C:DOCUME~1\LOCALS~1\Temp\mysql_server.msi.Verify that the file exists and that you can access it.
¿ÉÊÇÎÒÕÒ ......
ÇëÎÊÏÂÄܲ»ÄÜÔÙwindows϶¨ÆÚÇå¿ÕmysqlÒ»¸ö±íÖеÄÈ«²¿Êý¾Ý£¬ÓÃPHPʵÏÖ£¡
лл¸÷λÁË
¾Í±ÈÈçÒ»¸öÐÇÆÚÇå¿ÕÒ»´Î
±ÈÈçÿ¸öÐÇÆÚÁùÁãµãÇå¿ÕÒ»´Î£¡
ллÁË
¼Æ»®ÈÎÎñ...php....sql...truncate....OK
Äã¾ÍÕâ½ÓÔÚҳà ......
ÎÒµÄmysqlÔõôûÓа취дÈëÖÐÎÄÊý¾Ý£¿Ö»ÒªÊÇÊý¾ÝдÈëÊý¾Ý¿âʱ ¾Í»á±ä³ÉÈý¸öÎʺŠ£¿Çë½Ì¸ßÈË£¡£¡
linux? ÔõôдÈëµÄ
ÔÚmysqlÖÐÖ´ÐÐ show variables like 'character%'Ìù½á¹û³öÀ´¡£
ÔÚ°²×°MYSLQʱ½«Êý¾Ý¿âµÄ×Ö· ......
Çë¸ßÊÖÖ¸µã,ÎÒ¶ÔÒ»Õűí²éѯºóÔÙ¸üÐÂ,²éѯÊÇ×Ó²éѯ,±¨´í:
You can't specify target table 'a_table' for update in from clause
ÍêÕûSQLÓï¾äÊÇ
UPDATE a_table SET STATUS=0 WHERE ID=(SELECT MIN(ID) from a_tab ......