At 16:22 -0500 7/26/04, Ghate, Shishir wrote:
I looked at the SHOW COLUMNS statement and they have what I want,
but I need to condition off them. For example, I don't want to
execute an ALTER TABLE command to add a column if that column is
already there. I've tried IF DOES NOT EXIST SHOW COLUMN ...
followed by the ALTER TABLE command, but the if check doesn't seem
to work on SHOW COLUMNS.
Am I missing something, or is this just something that is not supported?
You can process the output of SHOW COLUMNS in your application language
and use the result to construct the ALTER TABLE statement.
I assume that you're using some kind of programming API to access MySQL
here. If you're asking "is this supported using SQL alone?" the
answer is no.
Thanks
Shishir Ghate
-----Original Message-----
From: Paul DuBois [mailto:[EMAIL PROTECTED]
Sent: Monday, July 26, 2004 2:21 PM
To: Ghate, Shishir; [EMAIL PROTECTED]
Subject: Re: SQL for detecting if Column/Index already exists?
At 14:08 -0500 7/26/04, Ghate, Shishir wrote:
Hello,
I am trying to write a db creation script that will create a
database as a well as repair an existing database. What I can't
seem to find is a set of key words that will allow me to detect if a
column or index already exists in a table and thus skip the creation
of the column or index. I've found the proper syntax to check for
table existance, but I can't find the syntax for column/index
existance.
If someone could point me to a set of docs or an example SQL
command, that would be great.
You could use the SHOW COLUMNS and SHOW INDEX statements?
--
Paul DuBois, MySQL Documentation Team
Madison, Wisconsin, USA
MySQL AB, www.mysql.com
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