table_name,concat(‘alter table `‘,table_name,‘` MODIFY ‘, column_name, ‘ ‘, data_type ,‘ auto_increment;‘) as ‘query script‘from information_schema.columns cwhere c.table_schema = ‘pv_2‘and c.column_key =‘PRI‘ and c.data_type in ( ‘int‘,‘bigint‘)and c.extra <> ‘auto_increment‘order by table_name; mysql 批量更新数据库主键为int，bigint 类型，字段为自增类型标签：sch lte post ...
TABLE `表名` MODIFY `字段名` TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP;一个表中只能出现一个 CURRENT_TIMESTAMP 属性的字段Mysql自动更新字段时间标签：update current log odi pre 设置 color default def 本文系统来源：https://www.cnblogs.com/xbblogs/p/8352962.html
9.12 增删改表字段 9.12.1 命令语法及默认添加用演示 1.命令语法： alter table 表名 add 字段 类型 其他 2.测试表数据 mysql> show create table student\G *************************** 1. row ***************************Table: student Create Table: CREATE TABLE `student` (`id` int(4) NOT NULL,`name` char(20) NOT NULL,`age` tinyint(2) NOT NULL DEFAULT ‘0‘,`dept` varchar(16) DEFAULT NULL ) ENGINE=InnoDB DEFA...
3字节，日期，格式：2014-09-18 time 3字节，时间，格式：08:42:30 datetime 8字节，日期时间，格式：2014-09-18 08:42:30 timestamp 4字节，自动存储记录修改的时间 year 1字节，年份 数值数据类型tinyint 1字节，范围（-128~127） 2^8 smallint 2字节，范围（-32768~32767）2^15 mediumint 3字节，范围（-8388608~8388607）2^23 int 4字节，范围（-2147483648~2147483647）2^31 bigint 8字节，范围（+-9.22*10的18次方）2^63 浮...
GROUP BY b.USER_ID; 很明显，这样在我的sql里面会报错。 所以我用了关联查询 on后跟了两个条件 select * from (select USER_ID,MAX(last_updated_date) group by USER_ID) as temp left join t_iov_help_feedback as t on temp.USER_ID=t.USER_ID and temp.last_updated_date=t.last_updated_date; 这样就能查出来了。先写这么多，以后有时间了再仔细研究论证。 mysql根据某个字段分组根据更新时间获取最新的记录标签：一个 ...
= ‘ ‘ 2.加入判断的方式，即可动态设置字段名每一个字段，都加入判断，符合判断则更新，即可动态设置字段名。注意：每一个判断进去的语句后面必须加逗号，否则同样会报错。 1 update TB_PRODUCT2 set 3 <if test="PRODUCT_IMG1 != null and PRODUCT_IMG1 != ‘‘">4 PRODUCT_IMG1 = ‘‘,5 </if>6 <if test="PARAMETER_IMG1 != n...
当更新字段缺少where语句时，mysql会提示一下错误代码： Error Code: 1175. You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column To disable safe mode, toggle the option in Preferences -> SQL Queries and reconnect. 0.000 sec 2 方案SET SQL_SAFE_UPDATES = 0; update 表名 set 字段1 = 字段2+1; SET SQL_SAFE_UPDATES = 1; 3 总结 这篇文章仅作为记录使用。 mysql更...
礼悟： 公恒学思合行悟，尊师重道存感恩。叶见寻根三返一，江河湖海同一体。 虚怀若谷良心主，愿行无悔给最苦。读书锻炼养身心，诚劝且行且珍惜。 数据、数据，命根就在数据。操作数据库一定要谨慎小心。给最苦 这里的代码，看看就好，要有自己的判断。遇到抉择，要不耻上下问。 mysql：5.7 os：Windows7 x64 代码及效果mysql> select * from t1; +------+-------+ | id...
select * from t1; +------+-------+ | id | name | +------+-------+ | 4 | Hello | | 2 | World | | 1 | nihao | | 3 | nihao | | 100 | nihao | +------+-------+ 5 rows in set (0.00 sec) 只看其中的一列mysql> select name from t1; +-------+ | name | +-------+ | Hello | | World | | nihao | | nihao | | nihao | +-------+ 5 rows in set (0.00 sec) mysql，关系型数据库管理系统，优秀，...
mysql> create table t2(2 -> name varchar(9) default ‘hello‘3 -> );4 Query OK, 0 rows affected (0.08 sec)5 6 mysql> desc t2;7 +-------+------------+------+-----+---------+-------+8 | Field | Type | Null | Key | Default | Extra |9 +-------+------------+------+-----+---------+-------+ 10 | name | varchar(9) | YES | | hello | | 11 +-------+------------+------+-----+------...
desc t1; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | name | varchar(10) | YES | | 未登记 | | +-------+-------------+------+-----+---------+-------+ 2 rows in set (0.00 sec)mysql> insert into t1 (id,name) value...
select * from t1; +------+-------+ | id | name | +------+-------+ | 4 | Hello | | 2 | World | | 1 | nihao | | 3 | nihao | | 100 | nihao | +------+-------+ 5 rows in set (0.00 sec)mysql> select * from t1 order by id asc; +------+-------+ | id | name | +------+-------+ | 1 | nihao | | 2 | World | | 3 | nihao | | 4 | Hello | | 100 | nihao | +------+-------+ 5 rows in s...
create table myT1(-> `null` int-> ); Query OK, 0 rows affected (0.08 sec)mysql> desc myt1; +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | null | int(11) | YES | | NULL | | +-------+---------+------+-----+---------+-------+ 1 row in set (0.00 sec) mysql，关系型数据库管理系统...
create table student(-> stdId int not null auto_increment primary key-> ); Query OK, 0 rows affected (0.08 sec)mysql> desc student; +-------+---------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+----------------+ | stdId | int(11) | NO | PRI | NULL | auto_increment | +-------+---------+------+--...
#!/bin/bash db_name="cert" mysql_user="root" mysql_passwd="34567" table_name=`mysql -u$mysql_user -p$mysql_passwd -e "select table_name from information_schema.tables where table_schema=‘$db_name‘ and table_type=‘base table‘;"|grep -v table_name` for a in $table_name do echo -e "\n$a 表中的字段\n" mysql -u$mysql_user -p$mysql_passwd -e "select * from $db_name.$a limit 1;"|sed -n "1p"|awk ‘{f...