Yao Feng wrote:
>
> I think the manual of mysql is few to satisfy a newbie in sql.I have
> one question in this:
> One DATABASE data;
> include two TABLE log and ip;
> What I want to do is:
> update (or substitute) the TABLE log 's COLUMN url with TABLE ip 's
> COLUMN newip IF some condition happens(such as both TABLE 's COLUMN flag
> are same).
>
> Any advices to do it? It confused me for a few days.
Hi Yao
If you have a UNIQUE or PRIMARY KEY on log, you can do this:
1) CREATE a temporary table with all columns like log.
2) INSERT INTO
temp_log (column1, column2, ...., url)
SELECT
log.colum1, log.column2, ..., ip.newip
FROM
log, ip
WHERE
log.flag=ip.flag
3) REPLACE INTO
log
SELECT
temp_log
4) DROP temp_log
You can hold temp_log for the next round and just delete the contents, if needed.
Tschau
Christian
