大约有 42,000 项符合查询结果（耗时：0.0307秒） [XML]
What is the most efficient/elegant way to parse a flat table into a tree?
... syntax.
WITH RECURSIVE MyTree AS (
SELECT * FROM MyTable WHERE ParentId IS NULL
UNION ALL
SELECT m.* FROM MyTABLE AS m JOIN MyTree AS t ON m.ParentId = t.Id
)
SELECT * FROM MyTree;
I tested recursive queries in MySQL 8.0 in my presentation Recursive Query Throwdown in 2017.
Below is...
Start an Activity with a parameter
I'm very new on Android development.
5 Answers
5
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PostgreSQL DISTINCT ON with different ORDER BY
...expression(s).
Official documentation
So you'll have to add the address_id to the order by.
Alternatively, if you're looking for the full row that contains the most recent purchased product for each address_id and that result sorted by purchased_at then you're trying to solve a greatest N per gr...
How to get form field's id in Django?
Is there any way to get the id of a field in a template?
4 Answers
4
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SQL - Update multiple records in one query
...1.config_value = 'value',
t2.config_value = 'value2';
Here is SQLFiddle demo
or conditional update
UPDATE config
SET config_value = CASE config_name
WHEN 'name1' THEN 'value'
WHEN 'name2' THEN 'value2'
ELSE config_val...
How can I retrieve Id of inserted entity using Entity framework? [closed]
I have a problem with Entity Framework in ASP.NET. I want to get the Id value whenever I add an object to database. How can I do this?
...
ViewParam vs @ManagedProperty(value = “#{param.id}”)
...ditional <f:event type="preRenderView" listener="#{bean.init}" /> inside the <f:metadata> to do initialization/preloading based on the set values. Since JSF 2.2 you could use <f:viewAction> for that instead.
Allows for nested <f:converter> and <f:validator> for more fi...
What is the difference between shallow copy, deepcopy and normal assignment operation?
... 6]
c = [a, b]
Using normal assignment operatings to copy:
d = c
print id(c) == id(d) # True - d is the same object as c
print id(c[0]) == id(d[0]) # True - d[0] is the same object as c[0]
Using a shallow copy:
d = copy.copy(c)
print id(c) == id(d) # False - d is now a n...
Possible to do a MySQL foreign key to one of two possible tables?
...blem I have three tables; regions, countries, states. Countries can be inside of regions, states can be inside of regions. Regions are the top of the food chain.
...
Getting the ID of the element that fired an event
Is there any way to get the ID of the element that fires an event?
22 Answers
22
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