I think this is half the answer (though you've implied the other half).
First, you prevent mysql from accepting duplicate rows by defining a PRIMARY
KEY or UNIQUE INDEX on whatever column or columns determine uniqueness. See
<http://dev.mysql.com/doc/mysql/en/CREATE_INDEX.html> for the details.
Then, you can INSERT without fear of creating duplicate rows. Adding IGNORE
tells mysql not to bother you with an error message if your INSERT is a
duplicate.
If it is possible that your current info supersedes what is already in the
table, you might want to take a look at the manual page for REPLACE,
<http://dev.mysql.com/doc/mysql/en/REPLACE.html>,
or, if you use mysql 4.1.x, INSERT...ON DUPLICATE KEY UPDATE...
<http://dev.mysql.com/doc/mysql/en/INSERT.html>.
Michael
emierzwa@stripped wrote:
> Silently ignore duplicate index inserts...
>
> insert IGNORE into PERSON ( NAME ) values ( 'Test')
>
> Ed
> -----Original Message-----
> From: Gerhard Gaupp [mailto:g.gaupp@stripped]
> Hello
>
> I'm looking for something like
>
> if not exists( select 1 from PERSON where NAME = 'Test' ) then
> insert into PERSON ( NAME ) values ( 'Test');
> end if;
>
> I did it with Sybase Database.
> I need to get Data from Excel and have to be shure that there is no data
> more than once in the table.
> So I have to generate a script with test, if this data is in teh table
> yet, or not, before inserting.
>
> Did You Understand? Sorry for my English
>
> Greetings from Germany
>
> Gerhard
>
