大约有 7,000 项符合查询结果（耗时：0.0263秒） [XML]
How to test if a string is JSON or not?
... with useful data or an error message string produced by the PHP function mysql_error() . How can I test whether this data is a JSON string or the error message.
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MySQL - ORDER BY values within IN()
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@Vladimir - yes, it is MySQL-specific. The question has the mysql tag.
– Ayman Hourieh
Jun 6 '09 at 1:10
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How do I find which transaction is causing a “Waiting for table metadata lock” state?
...ransactions waiting for locks:
SELECT TRX_ID, TRX_REQUESTED_LOCK_ID, TRX_MYSQL_THREAD_ID, TRX_QUERY
FROM INNODB_TRX
WHERE TRX_STATE = 'LOCK WAIT';
Reference - MySQL Troubleshooting: What To Do When Queries Don't Work, Chapter 6 - Page 96.
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How do I rename a column in a database table using SQL?
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This is not supported in MySQL, is it?
– ustun
Oct 21 '11 at 11:41
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ALTER TABLE without locking the table?
When doing an ALTER TABLE statement in MySQL, the whole table is read-locked (allowing concurrent reads, but prohibiting concurrent writes) for the duration of the statement. If it's a big table, INSERT or UPDATE statements could be blocked for a looooong time. Is there a way to do a "hot alter", li...
MySQL: What's the difference between float and double?
...someone changed a field from float to double. Wondering why, I checked the mysql documentation, but honestly didn't understand what the difference is.
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MQTT与TCP的区别 - 创客硬件开发 - 清泛IT社区，为创新赋能！
... Maori dictionary)。10. mqtt客户端connect时，可以带有用户名和密码，用于验证客户端。服务端可以根据clientid、IP地址、用户名等进行ACL访问控制。可以通过自定义应用消息实现客户端对服务端的身份验证。11. 有商业和开源的mqtt broke...
mysql query order by multiple items
..._activity ASC so sort direction for each column, default sort direction in mysql (with default configuration) is ASC.
– ZurabWeb
Jan 30 '14 at 20:29
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MySql - Way to update portion of a string?
I'm looking for a way to update just a portion of a string via MySQL query.
4 Answers
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How to find gaps in sequential numbering in mysql?
... SELECT @var:= max FROM ....; select * from .. WHERE seq < @max; with MySQL variables.
– Moshe L
Mar 25 '19 at 6:08
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