check for value in table, if exists, report another, else create itPosted by: Nick none Date: September 13, 2011 11:48AM Hi all, I am new to MySQL and looking for some quick help on how to do the following. My table is as follows: table name is 'table1' , contains columns ...
importmysql.connector# 连接数据库cnx=mysql.connector.connect(user='user',password='password',host='localhost',database='database')cursor=cnx.cursor()# 创建表create_table_query=""" CREATE TABLE IF NOT EXISTS users ( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(50) UNIQUE, age INT ); "...
)][table_options][partition_options][IGNORE | REPLACE][AS] query_expressionCREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name{ LIKE old_tbl_name | (LIKE old_tbl_name) } 有意思的是，这次看到的语法结构，与之前学习的创建数据库 语法结构 很像，但又不像。分为三段，这是因为创建数据表，可以用...
ERROR 1364 (HY000): Field 'username' doesn't have a default value insert into t_user(id,username,password) values(1,'lisi','123'); 1.15.2 唯一性约束 唯一性约束修饰的字段具有唯一性,不能重复。但可以为null。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 drop table if exists t_user...
drop tableifexists t_user;create tablet_user(id int,usernamevarchar(255)unique// 列级约束);insert into t_uservalues(1,'zhangsan');insert into t_uservalues(2,'zhangsan');ERROR1062(23000):Duplicate entry'zhangsan'forkey'username'insert intot_user(id)values(2);insert intot_user(id)values(...
/判断输入内容是否为空function IsNull(){var str = document.getElementById('str').value.trim();if(str.length==0){alert('对不起,文本框不能为空或者为空格!');//请将“文本框”改成你需要验证的属性名称!}}//判断日期类型是否为YYYY-MM-DD格式的类型function IsDate(){var mysql校验数据库的身份...
对于MariaDB,从10.2.1开始,其支持DROP CONSTRAINT子句,并引入了DEFAULT约束,还支持check约束。且在MariaDB 10.0.2版本之后,操作字段时甚至支持if exists和if not exists。包括如下情况: 1 2 3 4 5 6 7 8 9 10 11 12 13ADDCOLUMN[IFNOTEXISTS]ADDINDEX [IFNOTEXISTS]ADDFOREIGNKEY [IFNOTEXISTS]ADDPARTITION...
ELSE (R) ELSEIF (R) ENABLE ENCLOSED (R) ENCRYPTION[e] END ENDS ENGINE ENGINES ENUM ERROR ERRORS ESCAPE ESCAPED (R) EVENT EVENTS EVERY EXCHANGE EXECUTE EXISTS (R) EXIT (R) EXPANSION EXPIRE EXPLAIN (R) EXPORT EXTENDED EXTENT_SIZE FALSE (R) FAST FAULTS FETCH (R) FIELDS FILE FILE_BLOCK_...
--echo # --echo # some comments --echo # --disable_warnings DROP TABLE IF EXISTS t1; SET @@sql_mode='NO_ENGINE_SUBSTITUTION'; --enable_warnings SET SQL_WARNINGS=1; CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1); INSERT INTO t1 VALUES (2); SELECT * FROM t1; DROP TABLE ...
I need to check if a row exists, and update it if it does, or insert it if it doesn't. My table, 4 columns, id, file_id, user_id, shared. -- phpMyAdmin SQL Dump -- version 3.2.4 --http://www.phpmyadmin.net-- -- Host: localhost -- Generation Time: Mar 04, 2010 at 10...