大约有 19,000 项符合查询结果（耗时：0.0594秒） [XML]
select * vs select column
...the top of my head is when you want only the value of an indexed column in MySQL (for example, just to check for row existence), and you're using MyISAM storage engine, it'll grab the data from the MYI file, which could be in memory, and not even go to disk!
– Mike Sherov
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How do I add more members to my ENUM-type column in MySQL?
The MySQL reference manual does not provide a clearcut example on how to do this.
7 Answers
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How to 'insert if not exists' in MySQL?
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use INSERT IGNORE INTO table
see http://bogdan.org.ua/2007/10/18/mysql-insert-if-not-exists-syntax.html
there's also INSERT … ON DUPLICATE KEY UPDATE syntax, you can find explanations on dev.mysql.com
Post from bogdan.org.ua according to Google's webcache:
18th October 2007
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difference between primary key and unique key
I'm using mysql database. I have a confusion between primary key and unique key.
15 Answers
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Saving timestamp in mysql table using php
I have a field in a MySQL table which has a timestamp data type. I am saving data into that table. But when I pass the timestamp ( 1299762201428 ) to the record, it automatically saves the value 0000-00-00 00:00:00 into that table.
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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...
Get Insert Statement for existing row in MySQL
Using MySQL I can run the query:
15 Answers
15
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MySQL select 10 random rows from 600K rows fast
...imple, to gaps, to non-uniform with gaps.
http://jan.kneschke.de/projects/mysql/order-by-rand/
For most general case, here is how you do it:
SELECT name
FROM random AS r1 JOIN
(SELECT CEIL(RAND() *
(SELECT MAX(id)
FROM random)) AS id)
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How to create relationships in MySQL
... to do what the rest of the class is doing, but with raw SQL commands with MySQL instead of using Access.
8 Answers
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String concatenation in MySQL
I am using MySQL and MySQL Workbench 5.2 CE. When I try to concatenate 2 columns, last_name and first_name , it doesn't work :
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