日期格式 - DD-MM-YYYY 到 YYYY-MM-DD

Question

MySQL table has 2 columns - startdate and enddate

They hold dates in this format: 22-01-2016

When I was prototyping, I used MediumText.

Now, I want to switch to Date format. The default date format in PHPMyAdmin is YYYY-MM-DD

If I switch the columns to Date, my data turns into 0000-00-00.

Using PHP or MySQL, how do I reformat my data prior to going back into PHPMyAdmin to switch the columns to Date format?

Answer 1

You can use string to date function to update columns data before changing its structure

UPDATE table SET dateColumn = STR_TO_DATE(dateColumn, '%d-%m-%Y');

It will convert DD-MM-YYYY formatted dates to YYYY-MM-DD. After that you can just change structure of column to DATE

Answer 2

The easiest and most reliable way would be to split up the dates and rearrange them the other way round:

$parts = explode('-', $olddate);
$newdate = sprintf('%04d-%02d-%02d', $parts[2], $parts[1], $parts[0]);