Comments are causing errors in MySQL Script

Question

I'm using -- and # for comments in my SQL scripts but when I run, it returns error messages about syntax errors. When I take the comments out it runs fine. For examples below cause errors.

#################################################
# DELETE RECORDS FROM TABLE
#################################################

-- DELETE RECORDS FROM TABLE WHERE EXTRACT RECORDS CONTAIN DELETE

The only comment I can do is # at the beginning of a line which I guess is sufficient but I want to know why this doesn't work. Did this all the time in SQLServer.

Answer 1

Both ways are acceptable for commenting out lines in MySQL scripts. See MySQL's documentation on comments. The hash at the start of the line is acceptable, as is the double-hyphen as long as it is followed by a space, e.g.:

-- This line is valid a comment   

Not putting a space after the double hyphen will cause errors in mysql.

--This line is NOT a valid comment

If you are putting a space after the double-hyphens, there must be some other reason for the syntax errors. The example you posted works for me in MySQL without errors.

Answer 2

Comments in SQL start -- i.e. What you have and that works

But not starting with '#'

So put -- to start a comment

This is when the database is running in ANSI mode (I guess)