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MySQL error: key specification without a key length
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The error happens because MySQL can index only the first N chars of a BLOB or TEXT column. So The error mainly happens when there is a field/column type of TEXT or BLOB or those belong to TEXT or BLOB types such as TINYBLOB, MEDIUMBLOB, LONGBLOB, TINY...
String concatenation in Ruby
...;< but that is not the usual way
With string interpolation
source = "#{ROOT_DIR}/#{project}/App.config"
with +
source = "#{ROOT_DIR}/" + project + "/App.config"
The second method seems to be more efficient in term of memory/speed from what I've seen (not measured though). All three methods ...
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...
MySQL LIKE IN()?
...eing sufficient to give me the correct results, using LIKE as well allowed MySQL to reduce the result set considerably before having to use the slower REGEXP criteria.
– mpen
Feb 15 '12 at 0:11
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Sqlite or MySql? How to decide? [closed]
...buffer parts of your 1Tb database in your 32G of memory.
You need to use mysql or some other server-based RDBMS.
Note that MySQL is not the only choice and there are plenty of others which might be better for new applications (for example pgSQL).
Sqlite is a very, very nice piece of software, bu...
Change One Cell's Data in mysql
How can I change the data in only one cell of a mysql table.
I have problem with UPDATE because it makes all the parameters in a column change but I want only one changed. How?
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Remove duplicate rows in MySQL
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This is no longer support in 5.7.4, dev.mysql.com/doc/refman/5.7/en/alter-table.html
– Ray Baxter
Nov 25 '15 at 20:59
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MySQL Insert Where query
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MySQL INSERT Syntax does not support the WHERE clause so your query as it stands will fail. Assuming your id column is unique or primary key:
If you're trying to insert a new row with ID 1 you should be using:
INSERT INTO U...
How can I check MySQL engine type for a specific table?
My MySQL database contains several tables using different storage engines
(specifically myisam and innodb). How can I find out which tables are
using which engine?
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When to use MyISAM and InnoDB? [duplicate]
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Read about Storage Engines.
MyISAM:
The MyISAM storage engine in MySQL.
Simpler to design and create, thus better for beginners. No worries about the foreign relationships between tables.
Faster than InnoDB on the whole as a result of the simpler structure thus much less costs of server ...