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What are the differences between struct and class in C++?
...ate by
default. Members of a class defined
with the keywords struct or union
are public by default.
Additional difference: the keyword class can be used to declare template parameters, while the struct keyword cannot be so used.
...
MIN/MAX vs ORDER BY and LIMIT
...oks like MIN() is able to simply pluck the smallest value from the index ('Select tables optimized away' and 'NULL' rows) whereas the SORT and LIMIT still needs needs to do an ordered traversal of the index (106,000 rows). The actual performance impact is probably negligible.
It looks like MIN() i...
How do I check if a SQL Server text column is empty?
...
Actually, you just have to use the LIKE operator.
SELECT * FROM mytable WHERE mytextfield LIKE ''
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Can't choose class as main class in IntelliJ
...
Select the folder containing the package tree of these classes, right-click and choose "Mark Directory as -> Source Root"
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编程基础与事件状态 06：把任务与记录保存下来 · App Inventor 2 中文网
...120秒。
延迟回调按实际时间计算。
运行中重复开始不重置。
重启读取设置、记录和暂停快照。
暂停期间不扣时。
完成记录持久化。
到期与重复计时回调。
排查时先确定出错的是输入、状态、数据读取还是显示；用...
Correct way to add external jars (lib/*.jar) to an IntelliJ IDEA project
...ps for adding external jars in IntelliJ IDEA:
Click File from the toolbar
Select Project Structure option (CTRL + SHIFT + ALT + S on Windows/Linux, ⌘ + ; on Mac OS X)
Select Modules at the left panel
Select Dependencies tab
Select + icon
Select 1 JARs or directories option
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Using SSH keys inside docker container
... different base, and each of them begins a new stage of the build. You can selectively copy artifacts from one stage to another, leaving behind everything you don’t want in the final image.
Keeping this in mind here is my example of Dockerfile including three build stages. It's meant to create a...
How can I temporarily disable a foreign key constraint in MySQL?
Is it possible to temporarily disable constraints in MySQL?
10 Answers
10
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Avoid duplicates in INSERT INTO SELECT query in SQL Server
...
Using NOT EXISTS:
INSERT INTO TABLE_2
(id, name)
SELECT t1.id,
t1.name
FROM TABLE_1 t1
WHERE NOT EXISTS(SELECT id
FROM TABLE_2 t2
WHERE t2.id = t1.id)
Using NOT IN:
INSERT INTO TABLE_2
(id, name)
SELECT t1.id,
t1....
How to insert a line break in a SQL Server VARCHAR/NVARCHAR string
...NVARCHAR(100)
SET @text = 'This is line 1.' + CHAR(13) + 'This is line 2.'
SELECT @text
This prints out the following:
This is line 1.
This is line 2.
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