mysql optimization - If a mysql table cannot ensure that the field column lengths are consistent, does it not need to use char?

In a data table, if the length of each data column is fixed, then the length of each data row will also be fix...

From [MySQLdiscussion group] 2017-05-24 11:33:08 0  1  702

sql语句 - 请教关于mysql分组查询统计数据的问题

我有这么一张表，如下分别有三个字段：num, task_id, day {代码...} 问题： 我现在要在上面这个结果列表中，保持按照day顺序不变的情况下 获取最近30行task_id数据，要求task_id不能重复 ...

From [MySQLdiscussion group] 2017-04-17 16:23:43 0  2  702

MySQL，如何用一条sql来update两张表？

表A，字段1表B，字段1如何一条sql更新两张表？设置字段1=100，字段2=200update 表A，表B，set 表A.字段1......这样吗？

From [MySQLdiscussion group] 2017-04-17 15:34:06 0  4  702

如何把3个不同的MySQL数据库数据整合到一个MySQL数据库中？

现在有3个网站分别是discuz,phpcms,thinkphp开发的，他们有各自的用户数据，想把这3个MySQL数据库中的数据整合起来放到一个数据库中，应该如何操作最好呢？ 新建一个MYSQL数据库新设计数据表然后从3...

From [MySQLdiscussion group] 2017-04-17 15:14:20 0  3  702

java-web - Hibernate读取Mysql blob大字段数据

1.项目中用到了oauth2.0东西(基于spring-security)，在mysql数据库中有几张简单的表，目前我需要读取其中一张表oauth_access_token。 2.表中有两个blob的大字段，大字段存储的...

From [MySQLdiscussion group] 2017-04-17 13:41:55 0  1  702

ThinkPHP使用视图模型好还是MYSQL视图好

感觉ThinkPHP的视图模型不是很那个。

From [MySQLdiscussion group] 2017-04-17 13:25:32 0  2  702

mysql - SQL查询唯一字段时加上LIMIT 1会不会更快？

比如，用户的username是无重复的，如果查询某个username，可能他会把整个表都搜一遍。 如果我加入了LIMIT 1，他会不会在搜到这个username后立即停止搜索并返回呢？ 这种情况下速度是不是就会快一点啊？

From [MySQLdiscussion group] 2017-04-17 11:04:26 0  7  702

mysql - Query to modify the database optimization problem

I have a table with hundreds of thousands of data. Every time an event is triggered, all tables will be querie...

From [MySQLdiscussion group] 2017-05-18 10:46:43 0  2  701

Disabled form inputs will not appear in requests

I have some disabled inputs in my form and I want to send them to the server, but Chrome excludes them from th...

From [MySQLdiscussion group] 2023-10-14 18:01:00 0  2  699

Java - When inserting data with empty value into the database, it says that my data is too long.

When inserting null data into the database, the error Data truncation: Data too long for column 'REPLY_TYPE' a...

From [MySQLdiscussion group] 2017-05-25 15:08:09 0  2  699

mysql - 优惠券表应该怎么建，求帮助

优惠券使用规则的表应该怎么去建

From [MySQLdiscussion group] 2017-04-17 16:32:15 0  1  699

mysql UPDATE 数据与目标数据相同 返回0

mysql 当UPDATE 数据与目标数据相同 返回0 那这样我确定他是因为其它错误还是因为数据相同更新不成功!

From [MySQLdiscussion group] 2017-04-17 13:39:05 0  1  699

MySQL - Trigger to update the same table after insert operation

Here's what I'm trying to do: When there is a new INSERT into table ACCOUNTS, I need to update the row in ACCO...

From [MySQLdiscussion group] 2023-10-16 20:01:46 0  2  698

How to retrieve rows in column with highest value using SQL [duplicate]

I have a table in a document (here is a simplified version): id to content 11...21...12...13... How to select ...

From [MySQLdiscussion group] 2023-09-20 13:44:50 0  2  698

mysql - Access denied for user 'ODBC'@'localhost' (using password: NO)

控制台中输入MySQL报错Access denied for user 'ODBC'@'localhost' (using password: NO)

From [MySQLdiscussion group] 2017-04-17 15:05:57 0  1  698