大约有 7,000 项符合查询结果（耗时：0.0147秒） [XML]
update columns values with column of another table based on condition [duplicate]
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it's not working in mysql
– cikatomo
Sep 30 '15 at 19:30
22
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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...
Difference between string and text in rails?
...l is converted into its respective column type in query language.
with MySQL :string is mapped to VARCHAR(255)
- http://guides.rubyonrails.org/migrations.html
:string | VARCHAR | :limit => 1 to 255 (default = 255)
:text | TINYTEXT, TEXT, MEDIUMTEXT, or...
Windows下 C++网络延时检测 - C/C++ - 清泛网 - 专注C/C++及内核技术
...低延时、负载较低的服务器节点。例如：那么这个功能是如何实现的呢？...一般需要连接服务器后端的软件都有服务器节点网络延迟的检测，帮助选择低延时、负载较低的服务器节点。例如：
那么这个功能是如何实现的呢？...
中关村服务辐射百万创业者 - 资讯 - 清泛网 - 专注C/C++及内核技术
...间、人才、资本……成为拦在创业道路上的种种难题。
如何才能在日益变化的环境下更好地帮到创业者，成为摆在创业服务业面前的最大问题。6月25日，清控科创携手清华控股、北极光创投、完美时空、银杏天使、创业邦、盛...