Get top n records for each group of grouped results
The following is the simplest possible example, though any solution should be able to scale to however many n top results are needed: … Read more
MySQL
Insert auto increment primary key to existing table
I am trying to alter a table which has no primary key nor auto_increment column. I know how to add an primary key … Read more
How to store arrays in MySQL?
I have two tables in MySQL. Table Person has the following columns: id name fruits The fruits column may hold null or an … Read more
Format number to 2 decimal places
I would like to know how can I output a number with 2 decimal places, without rounding the original number. For example: 2229,999 … Read more
How can I use mySQL replace() to replace strings in multiple records?
We have a database that has a bunch of records with some bad data in one column, in which an embedded editor escaped … Read more
Mysql adding user for remote access
I created user [email protected]’%’ with password ‘password. But I can not connect with: mysql_connect(‘localhost:3306’, ‘user’, ‘password’); When I created user [email protected]’localhost’, I was … Read more
Access denied; you need (at least one of) the SUPER privilege(s) for this operation
So I try to import sql file into rds (1G MEM, 1 CPU). The sql file is like 1.4G mysql -h xxxx.rds.amazonaws.com -u … Read more
How do you manage databases in development, test, and production?
I’ve had a hard time trying to find good examples of how to manage database schemas and data between development, test, and production … Read more
Using backticks around field names
After reading a couple of answers and comments on some SQL questions here, and also hearing that a friend of mine works at … Read more
UPDATE multiple tables in MySQL using LEFT JOIN
I have two tables, and want to update fields in T1 for all rows in a LEFT JOIN. For an easy example, update … Read more
