增加表字段:ALTER TABLE tablename ADD [COLUMN] column_definition [FIRST | AFTER col_name] alter table [emp] add column [age] [int(3)]; 删除表字段:ALTER TABLE tablename DROP [COLUMN] col_name 字段改名:ALTER TABLE tablename CHANGE old_col_name column_definition [FIRST|AFTER col_name] 注...
**from > on> join > where > group by > with > having > select(**含重命名) > distinct > order by > limit 三、Update | Delete | 插入查询结果 3.1 Update 语法: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 UPDATE table_name SET column = expr [, column = expr ...] [WHERE ...
且column_definition->unireg_check == Field::NONE时,就会将column_definition->unireg_check值修改为TIMESTAMP_DNUN_FIELD,说明如果某一个列有这个值,则它表示的就是DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,但是通过跟踪代码发现,这个函数进来之后,根本没有执行这个赋值语句,因为column_definition...
SELECT [DISTINCT] column1, column2... FROM table_name [WHERE condition] [ORDER BY column [ASC|DESC]] [LIMIT count]; 2.2 字段选择方案 2.2.1 全字段查询 复制 SELECT * FROM employees; 2.2.2 指定字段查询 复制 SELECT name, department, hire_date FROM employees; 2.2.3 字段别名设置 复制 SELEC...
Use theColumnssubtab to display and edit all the column information for a table. With this subtab, you can add, drop, and alter columns. You can also use theColumnssubtab to change column properties such as name, data type, and default value. The following figure shows an example of th...
ADDINDEX indexname(column[, ...]) 删除索引 DROPINDEX indexnameONtablename 或: ALTERTABLEtablenameDROPINDEX indexname 创建视图 CREATE[ORREPLACE] [ALGORITHM={UNDEFINED|MERGE|TEMPTABLE}]VIEWviewname [(colname[, ...])] ASselect_statement [WITH[CASCADE|LOCAL]CHECKOPTION] ...
Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A 登录的时候加上-A参数 mysql -uroot –p123456 -A 修改表名称alter: 语法:alter table 表名rename 新表名; ...
we also had the limitations of earlier INSTANT ADD implementation in mind. Finally we came up with anewdesign which enables user to DROP column(s) from "any position" from a table with ALGORITHM=INSTANT. And thisdesigncan be easily consumed by the ADD COLUMN, ALGORITHM=INSTANT as well. So...
ALTER TABLE `table_name` ADD UNIQUE KEY `unique_index_name` (`column_name`[, `coumn_name_two`, ...]); 1.8.4.3 声明主键索引 (注意:只在当前表未显示声明主键的情况下才生效) ALTER TABLE `table_name` ADD PRIMARY KEY (`column_name`); ...
修复内核版本从8.0.1升级到8.0.2后,带有二级分区的分区表无法执行增加列(ADD COLUMN)操作的问题。 修复谓词条件中存在DEFAULT表达式时,并行查询可能导致的集群崩溃问题。 修复DLM策略执行时权限过高的问题。 修复归档表在存在降序索引时进行归档操作失败的问题。 修复对Blob列进行更新时,原记录的Blob空间无法回收的问题...