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How can I modify the size of column in a MySQL table?
... MODIFY command can do this more concisely.
Re the MEDIUMTEXT thing: a MySQL row can be only 65535 bytes (not counting BLOB/TEXT columns). If you try to change a column to be too large, making the total size of the row 65536 or greater, you may get an error. If you try to declare a column of V...
Throw an error in a MySQL trigger
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As of MySQL 5.5, you can use the SIGNAL syntax to throw an exception:
signal sqlstate '45000' set message_text = 'My Error Message';
State 45000 is a generic state representing "unhandled user-defined exception".
Here is a mo...
Get records with max value for each group of grouped SQL results
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There's a super-simple way to do this in mysql:
select *
from (select * from mytable order by `Group`, age desc, Person) x
group by `Group`
This works because in mysql you're allowed to not aggregate non-group-by columns, in which case mysql just returns the first...
How to add new column to MYSQL table?
I am trying to add a new column to my MYSQL table using PHP. I am unsure how to alter my table so that the new column is created. In my assessment table I have:
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Query to count the number of tables I have in MySQL
...long wait time. In that case, login should be done with the option -A, ie: mysql -uroot -p -A, and the command will work fast.
– azurecorn
Jul 21 at 12:28
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How do I update if exists, insert if not (AKA “upsert” or “merge”) in MySQL?
...SERT a row when it does not exist, or to UPDATE if it exists, using one MySQL query?
2 Answers
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How to get UTF-8 working in Java webapps?
...s" those characters.
To get UTF-8 working under Java+Tomcat+Linux/Windows+Mysql requires the following:
Configuring Tomcat's server.xml
It's necessary to configure that the connector uses UTF-8 to encode url (GET request) parameters:
<Connector port="8080" maxHttpHeaderSize="8192"
maxThreads...
“21天教你学会C++” - 创意 - 清泛网 - 专注C/C++及内核技术
...法（如果你已经会一门类似的语言），但你无法学到多少如何运用这些语法。简而言之，如果你是，比如说一个Basic程序员，你可以学会用C++语法写出Basic风格的程序，但你学不到C++真正的优点（和缺点）。那关键在哪里？Alan Per...
MySQL: @variable vs. variable. What's the difference?
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MySQL has a concept of user-defined variables.
They are loosely typed variables that may be initialized somewhere in a session and keep their value until the session ends.
They are prepended with an @ sign, like this: @var
Yo...
Commands out of sync; you can't run this command now
I am trying to execute my PHP code, which calls two MySQL queries via mysqli, and get the error "Commands out of sync; you can't run this command now".
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