删除列:altertable表名dropcolumn列名 修改列:altertable表名 modifycolumn列名 类型;-- 类型altertable表名 change 原列名 新列名 类型;-- 列名,类型添加主键:altertable表名addprimarykey(列名); 删除主键:altertable表名dropprimarykey;altertable表名 modify 列名int,dropprimarykey; 添加外键:altertable从表addco...
('t-shirt','medium'),('polo shirt','small'); 集合类型(set) A SET column can have a maximum of 64 distinct members. 示例: CREATE TABLE myset (col SET('a', 'b', 'c', 'd')); INSERT INTO myset (col) VALUES ('a,d'), ('d,a'), ('a,d,a'), ('a,d,d'), ('d,...
基本语法: INSERT INTO table_name [(column1, column2, ...)] VALUES (value1, value2, ...)[, (value1, value2, ...), ...]; 插入单条数据 INSERT INTO students (name, age, gender, class, score) VALUES ('张三', 20, '男', '计算机科学1班', 89.5); 插入多条数据 INSERT INTO stu...
mysql>CREATETABLEt1(aINT,bINT);QueryOK,0rowsaffected(0.06sec)mysql>SELECTtable_id,name,instant_colsFROMinformation_schema.innodb_tablesWHEREnameLIKE'%t1%';+---+---+---+|table_id|name|instant_cols|+---+---+---+|1065|test/t1|0|+---+---+---+1rowinset(0.22sec)mysql>SELECTtable_...
STORAGE DISK causes the column to be stored on disk, and STORAGE MEMORY causes in-memory storage to be used. The CREATE TABLE statement used must still include a TABLESPACE clause: mysql> CREATE TABLE t1 ( -> c1 INT STORAGE DISK, -> c2 INT STORAGE MEMORY -> ) ENGINE NDB; ERROR ...
TABLE table_name [ORDER BY column_name] [LIMIT number [OFFSET number]] 其实从语法上看,可以排序,也可以过滤记录集,不过比较简单,没有 SELECT 那么强大。 示例1 简单的建一张很小的表 y1,记录数为 10 条。 表t1,插入 10 条记录 mysql-(ytt/3305)->create table t1 (r1 int,r2 int);Query OK, ...
If you can't trust an SQL identifier (database / table / column name) because it is provided by a user, you should escape it with mysql.escapeId(identifier), connection.escapeId(identifier) or pool.escapeId(identifier) like this: var sorter = 'date'; var sql = 'SELECT * FROM posts...
-- # 2.准备表 -- #第一步:准备表 create table cmd_log( id int primary key auto_increment, cmd_name char(64), #命令的名字 sub_time datetime, #提交时间 user_name char(32), #是哪个用户过来执行这个命令 is_success enum('yes','no') #命令是否执行成功 ); create table err_log( id ...
expr2) With a single argument, this functionreturns the date or datetime expression expr as a datetime value. With two arguments, it adds the timeexpression expr2 to the date or datetime expression expr1 and returns the result as a datetime value. Returns NULL if expr, expr1, or ...
taddtime datetime default now(), primary key(tid ,tdeptId)) ENGINE=InnoDB DEFAULT CHARSET=utf8 PARTITION by list(tdeptId)( partition p0 VALUES in(1,2,3), PARTITION p1 VALUES in(4,5,6), PARTITION p2 VALUES in(7,8,9) ) hash分区表:根据用户提供的分区表达式的返回值来进行分布存储数据。