CAST This is just here to help me remember. In MySQL if you want to CAST an int into a string you use:
CAST(x AS CHAR)
I had assumed it would be VARCHAR but I was wrong. As a further reference here is info on all of the TYPES supported by MySQL. What I find interesting is the fact that MySQL does have a VARCHAR type but you can’t cast an int to it. Why Not? In the end it doesn’t matter too much; the CHAR option worked.
CONCAT
| A similarly odd behavior is how you concatenate strings in MySQL. I had thought I would use & or | but both of those return a 0 if you use them to concatenate. Instead you have to wrap all of the strings you want to concatenate up into a call to the CONCAT function like so: |
CONCAT('http://www.rawlinson.us/blog', page_name, '/datafiles/?file_id', CAST(file_id AS VARCHAR)) as url