临时表 replace in sql server 在写数据库命令语句时,我们经常会建一个测试表来试验自己写的语句是否正确,这里可以建一个临时表,用完之后自动删除很方便。顺便也学学临时表的用法。 create table #test ( idintidentity(1,1) notnull, n varchar(50) ) select*from #test insert into #test values('sun24'...
1.1 创建表: CREATE TABLE `test_tb` ( `id` int(10) unsigned NOT NULL auto_increment COMMENT ‘主键自增’, `name` char(30) default NULL COMMENT ‘姓名’, `address` char(60) default NULL COMMENT ‘地址’, `country` char(200) default NULL COMMENT ‘国家’, PRIMARY KEY (`id`) ) ENG...
There are options to either keep the existing data in the table or to clear the data from the table during the replace. The default is to keep all data. If you elect to clear all the data, your new table definition does not need to be compatible with the original version. In all cas...
SQL指南-IN IN IN 运算符可用于如果你知道一列你所想返回的精确值。 SELECT column_name FROM table_nameWHERE column_name IN (value1,value2,..) --- 原始表 (用于示例) --- 示例1 使用下面的SQL语显示LastName 等于"Hansen" 或者"Pettersen"的人 : SELECT * FROM Persons WHERE LastName IN ('Hans...
: test1 Create Table: CREATE TABLE `test1` ( `id` int(11) NOT NULL AUTO_INCREMENT, `age` int(11) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `uni_age` (`age`) ) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8 1 row in set (0.00 sec) 主库上进行replace之后,返回值是2...
mysql> CREATE TABLE t_replaceinto ( -> `id` int NOT NULL AUTO_INCREMENT, -> `c` int DEFAULT NULL, -> PRIMARY KEY (`id`), -> UNIQUE KEY `c` (`c`) -> ) ENGINE=InnoDB; Query OK, 0 rows affected (0.03 sec) 1. 2.
create table t1 (a int auto_increment primary key, b int, c int, unique key (b)); replace into t1(b,c) values (2,3) Step 1. 正常的插入逻辑 首先插入聚集索引,在上例中a列为自增列,由于未显式指定,每次Insert前都会生成一个不冲突的新值 ...
{SQLite3 ODBC Driver};Database=C:\sqlite\day_book.db" 'SQLITE的创建表的SQL语句 sqls = "CREATE TABLE 销售数据源(" & Join表头(arrString) & "PRIMARY KEY(商品id, name));" '开启对象 conn.Open Connstr '执行SQL语句生成表格 conn.Execute sqls '关闭对象 conn.Close MsgBox "Create Table ...
查找语句是SQL中最核心也最复杂的操作心 1、全列查找 直接把一个表的所有的列,和所有的行都查询出来~ select * from表名;* 就叫做"通配符",表示一个表的所有列 实例: -- 创建考试成绩表 create table exam_result ( id int, name varchar(20), ...
REPLACE works exactly like INSERT, except that if an old row in the table has the same value as a new row for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted. 如果新插入行的主键或唯一键在表中已经存在,则会删除原有记录并插入新行;如果在表中不...