大约有 7,000 项符合查询结果（耗时：0.0246秒） [XML]
How do I return rows with a specific value first?
...L Server, but that's because the syntax is non-standard and only works for MySQL. When using a CASE statement (which is standard SQL) SQL Server can very well use an expression in the ORDER BY clause. "too stupid to process equivalency tests" is simply wrong. If at all it should read: "does not supp...
how to emulate “insert ignore” and “on duplicate key update” (sql merge) with postgresql?
...skipped if it would violate a primary/unique key constraint. For instance, MySQL has INSERT IGNORE .
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INSERT … ON DUPLICATE KEY (do nothing)
... uses resources for the second action.
Use INSERT IGNORE ...,
Negative : MySQL will not show any errors if something goes wrong, so you cannot handle the errors. Use it only if you don’t care about the query.
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“use database_name” command in PostgreSQL
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If I'm not mistaken, databases in MySQL are more akin to schemas in PostgreSQL -- you can switch between those, but DBs in PostgreSQL are a whole different ballgame.
– mpen
May 10 '12 at 3:40
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How do you do a limit query in JPQL or HQL?
In Hibernate 3, is there a way to do the equivalent of the following MySQL limit in HQL?
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Socket send函数和recv函数详解以及利用select()函数来进行指定时间的阻塞 ...
...有情况下，发送开始调用是局部的：无论其它进程的状态如何，它立刻返回。如果这个调用使得一些系统资源用完，那么它将失败并返回 一个错误代码。高质量的MPI实现应保证这种情况只在“病态”时发生。即，一个MPI实现将...
How to find the lowest common ancestor of two nodes in any binary tree?
...ible. For both nodes in question construct a list containing the path from root to the node by starting at the node, and front inserting the parent.
So for 8 in your example, you get (showing steps): {4}, {2, 4}, {1, 2, 4}
Do the same for your other node in question, resulting in (steps not shown...
What is the difference between an ORM and an ODM?
...(Object Document Mapper) deals with documents. Am I right in assuming that mySQL is an example of ORM and MongoDB is a example of ODM?
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How to switch databases in psql?
In MySQL , I used use database_name;
12 Answers
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SQL Server - inner join when updating [duplicate]
...it works with UDPATE SET FROM JOIN WHERE? Does it depend on the version of mysql?
– Farside
Apr 28 '16 at 12:45
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