大约有 7,000 项符合查询结果（耗时：0.0159秒） [XML]
On duplicate key ignore? [duplicate]
...because it will additionally hold Next-Key lock on your indexes. More: dev.mysql.com/doc/refman/5.7/en/…
– Dzmitry Lazerka
Mar 14 '17 at 7:13
1
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How to remove not null constraint in sql server using query
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Why does this work and not the above accepted answer for mysql ?
– HopeKing
Feb 13 '18 at 8:47
1
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Altering a column to be nullable
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If this was MySQL syntax, the type would have been missing, as some other responses point out.
Correct MySQL syntax would have been:
ALTER TABLE Merchant_Pending_Functions MODIFY NumberOfLocations INT NULL
Posting here for clarity to ...
Delete terminal history in Linux [closed]
...can use previous commands again. Great feature. However, I started logging mysql into mysql with the sensitive details in the command.
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Can I change a column from NOT NULL to NULL without dropping it?
... I tried with alter column and it didn't work with the latest mysql server. I tried with modify column and it worked. Strange...
– Kostas Andrianos
Aug 19 '17 at 15:29
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常用Sql - 爬虫/数据库 - 清泛IT社区，为创新赋能！
本帖最后由 zqp2013 于 2015-3-17 22:06 编辑
mysql：drop table if exists tablename;
不能写成
drop table tablename if exists tablename;
mysql：建立索引Sql
CREATE TABLE tablename (
`ID` &nbs...
创业 比“直男癌”更可怕的是“技术癌” - 资讯 - 清泛网 - 专注C/C++及内核技术
...来的壁垒和防线。
预告：在后面的文章里，AA投资将对如何优化商业模式这个问题进行系统的介绍，分析如何通过找到现有商业模式的问题，寻找解决问题的路径，并实现商业模式的优化。
创业
Linux日志管理Rsyslog入门 - C/C++ - 清泛网移动版 - 专注IT技能提升
...这里着重与快速上手。
安装配置
我以CentOS为例，说明如何通过RPM来安装Rsyslog：
shell> cd /etc/yum.repos.d/
shell> wget http://rpms.adiscon.com/v8-stable/rsyslog.repo
shell> yum install rsyslog
安装完成后，我们可以查看一下到底都装了些什么东西...
Linux日志管理Rsyslog入门 - C/C++ - 清泛网移动版 - 专注IT技能提升
...这里着重与快速上手。
安装配置
我以CentOS为例，说明如何通过RPM来安装Rsyslog：
shell> cd /etc/yum.repos.d/
shell> wget http://rpms.adiscon.com/v8-stable/rsyslog.repo
shell> yum install rsyslog
安装完成后，我们可以查看一下到底都装了些什么东西...
Linux日志管理Rsyslog入门 - C/C++ - 清泛网移动版 - 专注IT技能提升
...这里着重与快速上手。
安装配置
我以CentOS为例，说明如何通过RPM来安装Rsyslog：
shell> cd /etc/yum.repos.d/
shell> wget http://rpms.adiscon.com/v8-stable/rsyslog.repo
shell> yum install rsyslog
安装完成后，我们可以查看一下到底都装了些什么东西...