Ò׽ؽØÍ¼Èí¼þ¡¢µ¥Îļþ¡¢Ãâ°²×°¡¢´¿ÂÌÉ«¡¢½ö160KB

Mysql Explain Ïê½â[Ç¿ÁÒÍÆ¼ö]

Mysql Explain Ïê½â
Ò».Óï·¨
explain < table_name >
ÀýÈç: explain select * from t3 where id=3952602;
¶þ.explainÊä³ö½âÊÍ
+----+-------------+-------+-------+-------------------+---------+---------+-------+------+-------+
| id | select_type | table | type  | possible_keys     | key     | key_len | ref   | rows | Extra |
+----+-------------+-------+-------+-------------------+---------+---------+-------+------+-------+
1.id
  ÎÒµÄÀí½âÊÇSQLÖ´ÐеÄ˳ÀûµÄ±êʶ,SQL´Ó´óµ½Ð¡µÄÖ´ÐÐ.
ÀýÈç:
mysql> explain select * from (select * from ( select * from t3 where id=3952602) a) b;
+----+-------------+------------+--------+-------------------+---------+---------+------+------+-------+
| id | select_type | table      | type   | possible_keys     | key     | key_len | ref  | rows | Extra |
+----+-------------+------------+--------+-------------------+---------+---------+------+------+-------+
|  1 | PRIMARY     | <derived2> | system | NULL              | NULL    | NULL    | NULL |    1 |       |
|  2 | DERIVED     | <derived3> | system | NULL              | NULL    | NULL    | NULL |    1 |       |
|  3 | DERIVED     | t3         | const  | PRIMARY,idx_t3_id | PRIMARY | 4       |      |    1 |       |
+----+-------------+------------+--------+-------------------+---------+---------+------+------+-------+
ºÜÏÔÈ»ÕâÌõSQLÊÇ´ÓÀïÏòÍâµÄÖ´ÐÐ,¾ÍÊÇ´Óid=3 ÏòÉÏÖ´ÐÐ.
2. select_type
¾ÍÊÇselectÀàÐÍ,¿ÉÒÔÓÐÒÔϼ¸ÖÖ
(1) SIMPL


Ïà¹ØÎĵµ£º

VB6.0ÈçºÎÓà libmySQL.dll API·ÃÎÊMYSQLÊý¾Ý¿â

MYSQL Ó¦ÓÃÊ®·Ö¹ã·¶£¬ºÜ¶àÍøÕ¾¼¸ºõ¶¼ÔÚÓÃËû£¬ÒòΪËûµÄСÇɺÍÁé»îÐԵȷ½ÃæÈÃÎÒ¾ö¶¨Òª¶ÔËû½øÐÐÑо¿£¬µ½ÏÖÔÚÒѾ­³É¹¦µÄ²»Óþ­¹ýODBC£¬ADOµÈ·½Ê½¾Í¿ÉÒÔ¶ÁÈ¡ºÍ¸üÐÂÊý¾Ý¡£
 
ºÃÁ˲»¶àÂÞ࣬ÒÔÏÂÎÒÀ´½éÉÜ×ܸö³ÌÐòµÄϸ½Ú:
 
£¨Ò»£©APIÉùÃ÷
 
1.  '·ÖÅä»ò³õʼ»¯ÊʺÏmysql_real_connect()µÄÒ»¸öMYSQL¶ÔÏñ¡ ......

¸ü¸ÄmysqlÊý¾Ý¿â±àÂëΪGBK

¸Õ¸Õ°²×°Íêmysqlºó
´ÓcmdÖнøÈëmysqlÊý¾Ý¿â
ÃüÁîÐÐÖÐÊäÈ룺
mysql -uroot -p123
½øÈëmysqlÊý¾Ý¿âÖÐ
ÃüÁîÐÐÖÐÊäÈë:
status;
²é¿´µ±Ç°Êý¾Ý¿âÖеıàÂë
ÈçÏ£º
--------------
mysql  Ver 14.12 Distrib 5.1.7-beta, for Win32 (ia32)
Connection id:       &nb ......

Red Hat enterprise linux 5 mysql°²×°²½Öè

Ò»¡¢°²×°·þÎñÆ÷¶Ë
£¨1£©¡¢ÔÚÓÐÁ½¸örmpÎļþµÄĿ¼ÏÂÔËÐÐÈçÏÂÃüÁ
[root@test1 local]# rpm -ivh MySQL-server-5.0.26-0.i386.rpm
ÏÔʾÈçÏÂÐÅÏ¢£º
warning: MySQL-server-5.0.26-0.i386.rpm: V3 DSA signature: NOKEY, key ID 5072e1f5
Preparing……¡¡¡¡¡¡¡¡¡¡¡¡¡¡##################################### ......

MYSQL »ñÈ¡µ±Ç°ÈÕÆÚ¼°ÈÕÆÚ¸ñʽ

MYSQL »ñÈ¡µ±Ç°ÈÕÆÚ¼°ÈÕÆÚ¸ñʽ
   »ñȡϵͳÈÕÆÚ£º  NOW()
   ¸ñʽ»¯ÈÕÆÚ£º    DATE_FORMAT(date, format)
               ×¢£º   date£ºÊ±¼ä×Ö¶Î
       ......

mysqlÔÚÔÙ´ÎÐ¶ÔØºó֨װ³öÏÖStart services²»ÄÜÆô¶¯

    ×î½ü×öÒ»¸öСÏîÄ¿£¬¸ÕºÃÓöµ½Õâ¸öÎÊÌ⣬ûʲôʱ¼äÈ¥½â¾öÕâ¸öÎÊÌ⣬´ó¸ÅÔÚÍøÉÏÕÒÁËһϣ¬Ëµ¸ÄʵÀýÃû£¬¸Ä×¢²á±í£¬ÏȲ»ÊǺܸҸģ¬±Ï¾¹¶Ô×¢²á±íÒ»Ö±¾õµÃÊǸö´óÉñ£¬²»¸ÒËæ±ã¶¯£¬½ñ¶ùÊÇ»í³öÈ¥ÁË£¬¾ÍÔÚ×¢²á±íÖвéÕÒËùÓдúmysql×ÖÑùµÄÐÅϢȫ²¿É¾³ý£¬×îºó¾¹È»³ÉÁË£¬µ±È»Ð¶Ôغóɾ³ý֮ǰËùÓеÄÏà¹ØÐÅÏ¢£¬°²×°ÎļþÄ¿ ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ