Full-text indexing was manually set up to work on the development server.

Now, I need to write a SQL script to programmatically set up Full-text
indexing on the staging server and then on the production server.

The SQL script must be rerunnable. It should handle the scenario where
full-text indexing already exists or not, per table, as necessary.

The SQL script works on the first pass successfully (because the staging
server did not have full-text indexing).

EXEC sp_fulltext_table 'tablename', 'create', 'Catalog', 'PK_tablename'
GO

The SQL script fails on the second pass on the staging server. Because it
tries to create the index that already exists.

So, I added a statement to drop the index before creating the index.

EXEC sp_fulltext_table 'tablename', 'drop'
GO
EXEC sp_fulltext_table 'tablename', 'create', 'Catalog', 'PK_tablename'
GO

That works because it drops an existing index, then creates the index.

However, the drop statement will fail if an index doesn't exist.

So then, how do I check for the existence of a table index before dropping it?

IF EXISTS ("statement to check for existence of a table index")
BEGIN
   EXEC sp_fulltext_table 'tablename', 'drop'
   GO
END
EXEC sp_fulltext_table 'tablename', 'create', 'Catalog', 'PK_tablename'
GO

I looked at sp_help_fulltext_tables, but it doesn't return TRUE/FALSE that I
could use in the if statement.

EXEC sp_help_fulltext_tables 'Catalog', 'tablename'
GO

Any suggestions?