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MySQL WHERE: how to write “!=” or “not equals”?
...ered Jul 10 '12 at 20:53
RolandoMySQLDBARolandoMySQLDBA
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MySQL - why not index every field?
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The link is for MS SQL Server; this question is for MySQL
– OMG Ponies
Mar 26 '11 at 23:38
6
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MySQL: Order by field size/length
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@mastazi according to MySQL documentation: OCTET_LENGTH() is a synonym for LENGTH().
– Heitor
Oct 1 '17 at 5:35
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Is there a MySQL option/feature to track history of changes to records?
I've been asked if I can keep track of the changes to the records in a MySQL database. So when a field has been changed, the old vs new is available and the date this took place. Is there a feature or common technique to do this?
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Multiple queries executed in java in single statement
...BC as it currently provides an exception even though it is possible in the MySQL query browser.
6 Answers
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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
5
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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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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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