大约有 40,000 项符合查询结果（耗时：0.0510秒） [XML]
Twitter image encoding challenge [closed]
...First, it generates a very large bignum to represent the data in the block table and the image size. The approach to this is similar to Sam Hocevar's solution -- kind of a large number with a radix that varies by position.
Then it converts that into a base of whatever the size of the character set...
MySQL select one column DISTINCT, with corresponding other columns
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try this query
SELECT ID, FirstName, LastName FROM table GROUP BY(FirstName)
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How to write a JSON file in C#?
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@RobertHarvey Liam's Json.Net link has a nice table showing what the differences are. Coming from the people that make it, of course you should take it with a grain of salt, but it is indeed better than the built-in things.
– Tim S.
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MySQL - SELECT WHERE field IN (subquery) - Extremely slow why?
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Rewrite the query into this
SELECT st1.*, st2.relevant_field FROM sometable st1
INNER JOIN sometable st2 ON (st1.relevant_field = st2.relevant_field)
GROUP BY st1.id /* list a unique sometable field here*/
HAVING COUNT(*) > 1
I think st2.relevant_field must be in the select, because other...
align right in a table cell with CSS
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It depends. I have a paragraph, which is block, inside a table cell (css display: table-cell), and if I give that paragraph a width of 100% it starts to respect text-align right. I assume defining a width isn't always the best thing.
– Costa
M...
Is having an 'OR' in an INNER JOIN condition a bad idea?
... to improve the speed of an immensely slow query (several minutes on two tables with only ~50,000 rows each, on SQL Server 2008 if it matters), I narrowed down the problem to an OR in my inner join, as in:
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Token Authentication for RESTful API: should the token be periodically changed?
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Also, you could expire tokens from the table by evicting old ones periodically in a cronjob (Celery Beat or similar), instead of intercepting the validation
– BjornW
Mar 15 '19 at 15:14
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mongodb: insert if not exists
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You may use Upsert with $setOnInsert operator.
db.Table.update({noExist: true}, {"$setOnInsert": {xxxYourDocumentxxx}}, {upsert: true})
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Oracle “Partition By” Keyword
...ment for every employee record. (It is as if you're de-nomalising the emp table; you still return every record in the emp table.)
emp_no dept_no DEPT_COUNT
1 10 3
2 10 3
3 10 3 <- three because there are three "dept_no = 10" records
4 20 2
5 ...
SQL set values of one column equal to values of another column in the same table
I have a table with two DATETIME columns.
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