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Importance of varchar length in MySQL table
I have a MySQL table where rows are inserted dynamically. Because I can not be certain of the length of strings and do not want them cut off, I make them varchar(200) which is generally much bigger than I need. Is there a big performance hit in giving a varchar field much more length than necessar...
MySQL get the date n days ago as a timestamp
In MySQL, how would I get a timestamp from, say 30 days ago?
3 Answers
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Best lightweight web server (only static content) for Windows [closed]
...r the Windows OS. It includes the latest versions of Apache2, Perl5, PHP5, MySQL5, phpMyAdmin and more. No installation required. No registry dust. Just unpack and fire up.
– Piotr
Apr 14 '16 at 13:35
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How does MySQL process ORDER BY and LIMIT in a query?
... @Green, you're mistaken. Read this for the explanation: dev.mysql.com/doc/refman/5.7/en/limit-optimization.html When the ORDER BY column is indexed, it may return records in a different order than without the LIMIT, when there are more than 1 records with the same value in that column...
Does MySQL foreign_key_checks affect the entire database?
When I execute this command in MySQL:
6 Answers
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Error 1046 No database Selected, how to resolve?
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You need to tell MySQL which database to use:
USE database_name;
before you create a table.
In case the database does not exist, you need to create it as:
CREATE DATABASE database_name;
followed by:
USE database_name;
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How to get the sizes of the tables of a MySQL database?
I can run this query to get the sizes of all tables in a MySQL database:
16 Answers
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MySQL INSERT INTO table VALUES.. vs INSERT INTO table SET
...ll, both syntaxes are equivalent. The first is SQL standard, the second is MySQL's extension.
So they should be exactly equivalent performance wise.
http://dev.mysql.com/doc/refman/5.6/en/insert.html says:
INSERT inserts new rows into an existing table. The INSERT ... VALUES and INSERT ... SET...
How can you determine how much disk space a particular MySQL table is taking up?
Is there a quick way to determine how much disk space a particular MySQL table is taking up? The table may be MyISAM or Innodb.
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Is there a MySQL command to convert a string to lowercase?
I have a MySQL database of keywords that are presently mixed-case. However, I want to convert them all to lowercase. Is there an easy command to do this, either using MySQL or MySQL and PHP?
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