当然用户还可以通过 ALTER TABLE来创建约束,并且可以定义用户所希望的约束名,如下面这个例子: mysql> alter table u add unique keyuk_id_card (id_card); Query OK, 0 rows affected (0.03 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> select c
Add Time in SQL HH:MM:SS to another HH:MM:SS Adding a column to a large (100 million rows) table with default constraint adding a extra column in a pivot table created uisng T-SQL Pivot Table query Adding a partition scheme to an existing table. Adding a Value to a 'date' Column ...
mysql> create table A (id int, name varchar(20)); Query OK, 0 rows affected (0.02 sec) mysql> insert into A values (1, "张三疯"), (2, "夏洛特"), (3, "熊大"), (4, "刻晴"), (5, "急先锋"); Query OK, 5 rows affected (0.01 sec) Records: 5 Duplicates: 0 Warnings: 0...
1 select_type: SIMPLE table:b type: ref possible_keys: indcompanyid key: ind_companyid keylen: 5 ref sakila.a.company_id rows: 1 Extra: Using where;Using index 2 rows in set (0.00 sec) 每个列的解释如下: select_type:表示 的类型,常见的取值有(简单表,即不使用连接...
GreatSQL社区 8声望6粉丝 GreatSQL是由万里数据库维护的MySQL分支,专注于提升MGR可靠性及性能,支持InnoDB并行查询特性,是适用于金融级应用的MySQL分支版本。 « 上一篇 MySQL 8.0.32如期而至 下一篇 » “采访”ChatGPT看看它对我们GreatSQL社区有什么看法 ...
MySQL> call p1; #这里第二次操作,直接执行update这句SQL的execute。 Query OK, 0 rows affected (13.78 sec) #接着我们执行表结构的更新。 MySQL> alter table t1 add i int; Query OK, 0 rows affected (0.41 sec) Records: 0 Duplicates: 0 Warnings: 0 ...
MySQL> alter table t1 add i int;Query OK, 0 rows affected (0.41 sec)Records: 0 Duplicates: 0 Warnings: 0#然后再次执行sp,就会发现这次执行了这句SQL的prepare再进行execute。MySQL> call p1;Query OK, 0 rows affected (34.24 sec) 二、代码跟踪...
is_unique Zero duplicates agnostic is_primary_key Zero duplicates agnostic are_complete Zero nulls on group of columns agnostic are_unique Composite primary key check agnostic is_composite_key Zero duplicates on multiple columns agnostic is_greater_than col > x numeric is_positive col > 0 numeric...
What to doCheck for duplicate field names and change the duplicates to distinct field names. Top of Page ACCWeb103079 Error textType mismatch in expression. What it meansThe types on either side of the join are incompatible or the field types compared are incompatible types. For example,...
Adding multiple rows to a datatable Adding multiple worksheet to Excel using Openxml Adding new columns dynamically Adding results of SQL query to an iEnumerable string adding scrollbar to dropdownlist Adding values inside the datatable to a Dictionary in VB.net Adjust printing to fit sizes (A4 ...