You can use GROUP_CONCAT
:
SELECT person_id,
GROUP_CONCAT(hobbies SEPARATOR ', ')
FROM peoples_hobbies
GROUP BY person_id;
As Ludwig stated in his comment, you can add the DISTINCT
operator to avoid duplicates:
SELECT person_id,
GROUP_CONCAT(DISTINCT hobbies SEPARATOR ', ')
FROM peoples_hobbies
GROUP BY person_id;
As Jan stated in their comment, you can also sort the values before imploding it using ORDER BY
:
SELECT person_id,
GROUP_CONCAT(hobbies ORDER BY hobbies ASC SEPARATOR ', ')
FROM peoples_hobbies
GROUP BY person_id;
As Dag stated in his comment, there is a 1024 byte limit on the result. To solve this, run this query before your query:
SET group_concat_max_len = 2048;
Of course, you can change 2048
according to your needs. To calculate and assign the value:
SET group_concat_max_len = CAST(
(SELECT SUM(LENGTH(hobbies)) + COUNT(*) * LENGTH(', ')
FROM peoples_hobbies
GROUP BY person_id) AS UNSIGNED);
Connecting to MYSQL with Python 2 in three steps
1 - Setting
You must install a MySQL driver before doing anything. Unlike PHP, Only the SQLite driver is installed by default with Python. The most used package to do so is MySQLdb but it's hard to install it using easy_install. Please note MySQLdb only supports Python 2.
For Windows user, you can get an exe of MySQLdb.
For Linux, this is a casual package (python-mysqldb). (You can use sudo apt-get install python-mysqldb
(for debian based distros), yum install MySQL-python
(for rpm-based), or dnf install python-mysql
(for modern fedora distro) in command line to download.)
For Mac, you can install MySQLdb using Macport.
2 - Usage
After installing, Reboot. This is not mandatory, But it will prevent me from answering 3 or 4 other questions in this post if something goes wrong. So please reboot.
Then it is just like using any other package :
#!/usr/bin/python
import MySQLdb
db = MySQLdb.connect(host="localhost", # your host, usually localhost
user="john", # your username
passwd="megajonhy", # your password
db="jonhydb") # name of the data base
# you must create a Cursor object. It will let
# you execute all the queries you need
cur = db.cursor()
# Use all the SQL you like
cur.execute("SELECT * FROM YOUR_TABLE_NAME")
# print all the first cell of all the rows
for row in cur.fetchall():
print row[0]
db.close()
Of course, there are thousand of possibilities and options; this is a very basic example. You will have to look at the documentation. A good starting point.
3 - More advanced usage
Once you know how it works, You may want to use an ORM to avoid writing SQL manually and manipulate your tables as they were Python objects. The most famous ORM in the Python community is SQLAlchemy.
I strongly advise you to use it: your life is going to be much easier.
I recently discovered another jewel in the Python world: peewee. It's a very lite ORM, really easy and fast to setup then use. It makes my day for small projects or stand alone apps, Where using big tools like SQLAlchemy or Django is overkill :
import peewee
from peewee import *
db = MySQLDatabase('jonhydb', user='john', passwd='megajonhy')
class Book(peewee.Model):
author = peewee.CharField()
title = peewee.TextField()
class Meta:
database = db
Book.create_table()
book = Book(author="me", title='Peewee is cool')
book.save()
for book in Book.filter(author="me"):
print book.title
This example works out of the box. Nothing other than having peewee (pip install peewee
) is required.
Best Answer
Updating an entry:
A simple increment should do the trick.
Insert new row, or Update if already present:
If you would like to update a previously existing row, or insert it if it doesn't already exist, you can use the
REPLACE
syntax or theINSERT...ON DUPLICATE KEY UPDATE
option (As Rob Van Dam demonstrated in his answer).Inserting a new entry:
Or perhaps you're looking for something like
INSERT...MAX(logins)+1
? Essentially you'd run a query much like the following - perhaps a bit more complex depending on your specific needs: