That is not valid syntax.
SQL> select count(t.*) as x from dual t;
select count(t.*) as x from dual t
ERROR at line 1:
ORA-01747: invalid user.table.column, table.column, or column specification
SQL> select count(*) as x from dual t;
Here's a workaround that gave me what I wanted without addressing my question. Documenting it here in case it's useful to someone.
I was able to put the final pass/fail-checking script in a separate action in Toad's Automation Designer, with a separate output file. The first several scripts for each test write to one file, and the last step of each test ...
If you were running via SQL*Plus, you could use set feedback off to suppress those messages. TOAD supports a subset of SQL*Plus commands so I'm not certain that it would support turning feedback off but I would expect that it would.
Personally, though, I'd strongly prefer moving away from a reliance on dbms_output here. Whatever you build is going to get ...
You can create an external table that references the data in your CSV.
You'll need a directory object creating that points to the location on the file system; in this case MY_DIR.
CREATE TABLE update_ids_ext
( TYPE ORACLE_LOADER
DEFAULT DIRECTORY my_dir