The MySQL ORDER BY clause let’s you easily order in fields in ascending or descending order however occasionally you’ll want to have a specific order

Take for instance if you have a list of products on a sales site ordered by name. Your boss tells you he wants to show one (or several) products before all others on the page. At this point you have 2 options – add a ‘special’ column in the table and do an ORDER BY special, name – which would only work if he wanted these special products in alphabetical or reverse alphabetical order – or use a UNION with multiple SELECT queries. Neither are great options. This is where the FIELD() function comes in.

The rows ordered by FIELD() will appear at the end of your table, so to get them appearing at the top just add DESC and put enter your FIELD() arguments in reverse order. All rows not specifically ordered with FIELD() will remain unordered unless specified otherwise. Here’s an example.

If the ID of the products your boss wants to appear first are 36, 40, 12 respectively, we can order like so:

SELECT *
FROM products
ORDER BY FIELD(id, 12, 40, 36) DESC, name

There is no limit to the number of arguments you can add and they must be the same data type as your field.

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When paginating data on your website you’ll probably have a query something like the following:

SELECT *
FROM my_table
LIMIT 0,50

However in doing so, chances are you’ll want to have a ‘Showing x-y of z rows‘ clause at the top of your table. Retrieving that z value can be quite a hassle – it’d be very ugly to need to execute the same query again sans the LIMIT clause. Recently I’ve come across an easy way of accomplishing this in MySQL – the FOUND_ROWS() function.

To use it is simple. In your first query place SQL_CALC_FOUND_ROWS after the SELECT keyword like so:

SELECT SQL_CALC_FOUND_ROWS *
FROM my_table
LIMIT 0,50

Then immediately afterwards execute this query to return the total number of rows before the LIMIT clause was executed:

SELECT FOUND_ROWS()

That’s it. Make sure to use the second query straight after the first or the result count will be lost.

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UPDATE: This script has been superseded by my Cloud Database Backup script. It’s advised you use that instead.

If you’re a developer you should back up your data. Go ahead – do it, do it now. Okay, now that we’ve got that out of the way here’s a nice automated solution to backing up your MySQL databases and optionally uploading to Amazon S3 for added safety.

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