MySQL中You can‘t specify target table for update in FROM clause错误的意思是说，不能先select出同一表中的某些值，再update这个表(在同一语句中)。 例如下面这个sql：update tms_jyxx_mx
set gg_dm =‘1004‘where jyxx_id
in (SELECTt1.jyxx_id as jyxx_idFROMtms_jyxx t1,tms_jyxx_mx t2WHEREt1.sjmc =‘保定白沟新城铭磊加油站‘AND t1.jyxx_id = t2.jyxx_idAND t2.ljqh =‘14‘AND t2.jysj >=‘2019-04-30 10:17:22‘AN...
-- MySQL 5.7 CLUSTER NDB 7.5 -- 创建undo logfile groupcreate logfile group lg_1 ADD UNDOFILE ‘undo_1.log‘ INITIAL_SIZE 1024M undo_buffer_size 8M ENGINE NDBCLUSTER; -- 增加 logfileALTER logfile group lg_1 ADD UNDOFILE ‘undo_2.log‘ initial_size 1024M ENGINE NDBCLUSTER; -- 创建tablespaceCREATE TABLESPACE ts1 ADD DATAFILE ‘data...
MySQL 列，可选择的数据类型（通过sql命令查看：help create table;） BIT[(length)]| TINYINT[(length)] [UNSIGNED] [ZEROFILL]| SMALLINT[(length)] [UNSIGNED] [ZEROFILL]| MEDIUMINT[(length)] [UNSIGNED] [ZEROFILL]| INT[(length)] [UNSIGNED] [ZEROFILL]| INTEGER[(length)] [UNSIGNED] [ZEROFILL]| BIGINT[(length)] [UNSIGNED] [ZEROFILL]| REAL[(length,decimals)] [UNSIGNED] [ZEROFILL]| DOUBLE[(length,decimals)]...
SELECTcount(*) from (SELECT province_code as area_id, count(*) from t_cas_rural_selected GROUPBY province_code
UNIONallSELECT city_code as area_id, COUNT(*) from t_cas_rural_selected GROUPBY city_code
UNIONallSELECT county_code as area_id, COUNT(*) from t_cas_rural_selected GROUPBY county_code)
as tTotal如上，后面加个 as tablename 就可以了，例如："as tTotal"mysql union出错: "Every derived table m...
mysql中You can‘t specify target table for update in FROM clause错误的意思是说，不能先select出同一表中的某些值，再update这个表(在同一语句中)。 例：DELETE from sys_org_relation where pOrgid in (select porgId from sys_org_relation r where r.corgid=‘客户id‘ and relationType=1112) and and relationType=1213;该语句中要操作的sys_org_relation 表条件也是来自sys_org_relation 表查询的结果，此时会抛出...
今天服务器当机了,重启后就发现了如下错误:Table ‘./mysql/proc’ is marked as crashed and should be repaired解决方法:repair table mysql.proc;原文：http://www.cnblogs.com/littlehb/p/4573356.html
1. 获取所有表结构(TABLES)SELECT * FROM information_schema.TABLES WHERE TABLE_SCHEMA=‘数据库名‘; TABLES表：提供了关于数据库中的表的信息（包括视图）。详细表述了某个表属于哪个schema，表类型，表引擎，创建时间等信息。各字段说明如下: 字段含义table_catalog数据表登记目录table_schema数据表所属的数据库名table_name表名称table_type表类型[system view|base table]engine使用的数据库引擎[MyISAM|CSV|InnoDB]ve...
登录数据库后，选择数据库时发现以下提示，mysql> use testReading table information for completion of table and column namesYou can turn off this feature to get a quicker startup with -ADatabase changedmysql> 意思是 预读这个库中表以及表列信息，一般原因是当库中表很多，表中数据很大时，就会出现执行use <库名>后半天没反应，连接很慢的情况，解决办法就是 -A 方式登录数据库，不会预读库中表信息。shell> mysql...
查看information_schema.tables：DESC information_schema.TABLES
TABLE_SCHEMA ---->库名
TABLE_NAME ---->表名
ENGINE ---->引擎
TABLE_ROWS ---->表的行数
AVG_ROW_LENGTH ---->表中行的平均行（字节）
INDEX_LENGTH ---->索引的占用空间大小（字节）使用案例：查询整个数据库中所有库和所对应的表信息：SELECT table_schema,GROUP_CONCAT(table_name)
FROM information_schema.tables
GROUP BY tab...
1. show databases mysql> show databases;+--------------------+| Database |+--------------------+| information_schema || mysql || performance_schema || test |+--------------------+4 rows in set (0.00 sec) 2. use database_namemysql> use testDatabase changed 3. show tables mysql> show tables;+----------------+| Tables_in_test |+----------------+| user ...
MySQL数据库插入数据出现ERROR 1526 (HY000): Table has no partition for value xxx工作的时候发现无法插入数据，报错：ERROR 1526 (HY000): Table has no partition for value xxx根据字面意思可以猜测大概是值已经超出了分区的范围，查询表结构发现此表创建了分区，并且设定了规则是按照ID范围存储数据，当插入的数据最后的分区ID值要大时，报错。解决方法可以直接添加分区即可。为验证问题，创建表：/************************...
Q: How do I see what the character set that a MySQL database, table and column
are in? Is there something like SHOW CHARACTER SETFOR mydatabase; and SHOW CHARACTER SETFOR mydatabase.mytable; and SHOW CHARACTER SETFOR mydatabase.mytable.mycolumn;A:How do I see what the character set that a MySQL database, table and column
are in? Is there something likeSHOW CHARACTER SETFOR mydatabase;andSHOW CHA...
一.mysql 执行select 的时候报Table错误：is marked as crashed and last (automatic?)解决方法如下：找到mysql的安装目录的bin/myisamchk工具，在命令行中输入： myisamchk -c -r ../data/dedecmsv4/dede_archives.MYI然后myisamchk 工具会帮助你恢复数据表的索引。重新启动mysql，问题解决。问题分析：1、错误产生原因，有网友说是频繁查询和更新dede_archives表造成的索引错误，因为我的页面没有静态生成，而是动态页面，因此比...
mysql The used table type doesn’t support FULLTEXT indexes是不支持全文索引，解决方案:1、停掉mysql服务2、打开my.ini,搜索default-storage-engine=你搜索到的应该是default-storage-engine=INNODB3、把INNODB改成MyISAM4、重新启动Mysql原文：http://www.cnblogs.com/zhang36/p/7722822.html
SELECT uin,account,password,create_user_uin_tree FROM sys_user结果：表中的create_user_uin_tree标识该条记录由谁创建。创建新用户时，根据当前登录用户的uin及新创建的用户uin，有如下SQL:select concat(ifNULL(create_user_uin_tree,concat(‘_‘,2,‘_‘)),‘|_‘,‘97‘,"_") from sys_user where uin=2结果： 那么修改的create_user_uin_tree的标识SQL为：update sys_user set create_user_uin_tree=(select concat(ifNU...
show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| database |
| mysql |
| newbases |
| performance_schema |
| test |
+--------------------+
6 rows in set (0.00 sec)
mysql> use newbases;
Database changed