Tags: mysql
Find MYSQL Duplicate records
In : mysql, Posted by admin on Mar.03, 2009
If the database has a table call employees. The values are:
ID Name
1 a
2 b
3 a
4 c
5 b
You want to find the duplicate record but not the first one (ie, ID# 3 and 5). You can do the following:
select id from employees where id not in (select distinct id from employees group by name);
How FriendFeed uses MySQL to store schema-less data
In : mysql, Posted by admin on Mar.03, 2009
Here is a posting about how FriendFeed uses MySQL to store the Json object. Then it creates separate table for each meta field to store the meta data. I use similar method to store all the static data (for example, order payment and transaction information). This method is good for data which is relatively stable.
mysql output csv file
In : mysql, Posted by admin on Oct.10, 2008
Here is the code to output result to csv file.
SELECT order_id,product_name,qty
FROM orders
INTO OUTFILE '/tmp/orders.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'