MySQL, adding a string to all column values

Question

Have a MySQL database table with 2 columns: id, url

The url column has values like 'http://www.example.com/'.

I need to add a string like 'http://www.x.com?redirect=' to the beginning of all the column values - ie to change the values like this: http://www.example.com/ ===> http://www.x.com?redirect=http://www.example.com/

Anyone has some clues to how I can do that?

I have looked into using CONCAT(), but so far I haven't been able to make it work :(

Thanks a lot for your help, Louisa

Answer 1

Yes, you use can use CONCAT :

SELECT CONCAT('http://www.x.com?redirect=', url) AS url
FROM yourtable

See it working online: sqlfiddle

Answer 2

使用concat会像这样：

update table set url=concat('http://www.x.com?redirect=',url);

Answer 3

You can do this:

Update myTable
SET data= (SELECT CASE WHEN data IS NULL THEN '' ELSE data END AS data WHERE id = 1) + 'some text'
WHERE id = 1

field = field + value does not work when field is null.

Answer 4

Take a look at code snippet from this SO answer :

update t set data=concat(data, 'a');

Something similar should work:

update t set data=concat('http://www.x.com?redirect=', data);