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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
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App Inventor 2 DynamicComponents 拓展：动态创建AI2组件对象 · App Inventor 2 中文网
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通过 JSON 字符串创建组件。请参阅Wiki，了解如何创建自己的模板。
从屏幕和组件列表中移除指定 ID 的组件。由于该组件已被删除，因此你可以再次使用该 ID...
Does MySQL ignore null values on unique constraints?
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Yes, MySQL allows multiple NULLs in a column with a unique constraint.
CREATE TABLE table1 (x INT NULL UNIQUE);
INSERT table1 VALUES (1);
INSERT table1 VALUES (1); -- Duplicate entry '1' for key 'x'
INSERT table1 VALUES (NULL);...
SQL Server: SELECT only the rows with MAX(DATE)
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For MySql you can do something like the following:
select OrderNO, PartCode, Quantity from table a
join (select ID, MAX(DateEntered) from table group by OrderNO) b on a.ID = b.ID
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What is the difference between MySQL Server and MySQL Client
...nstall both but what are the differences between the client and server for MySQL.
3 Answers
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How do I calculate square root in Python?
...valuate to 0.
And for the record, the preferred way to calculate a square root is this:
import math
math.sqrt(x)
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为什么你有10年经验，但成不了专家？ - 杂谈 - 清泛网 - 专注C/C++及内核技术
...有10年经验，但成不了专家？转载自微信公众号李叫兽。如何成为一个领域的专家？有人说主要靠经验，有人说靠天赋，但是大量的研究发现：不论是经验还是天赋，都不是成为...如何成为一个领域的专家？
有人说主要靠经验...
Unknown column in 'field list' error on MySQL Update query
I keep getting MySQL error #1054, when trying to perform this update query:
11 Answers
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Find most frequent value in SQL column
...+1 for using standard SQL that will work in any database (whereas LIMIT is MySQL specific, TOP is SQL Server specific).
– Dylan Smith
Jul 20 '18 at 14:46
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推动“一带一路”IT产业怎么走 - 资讯 - 清泛网 - 专注C/C++及内核技术
...味着基础设施建设的提速，还有科技和文化的互联互通。如何把握机会借助“一带一路”走出去，如何在IT产业更为发达的地区站稳脚跟并抓住欠发达地区的市场，这成为目前中国IT企业必须解决的问题。“一带一路”倡议对其...