1.5.1 An English letter follows closely in comment symbol '/*'
In SQL*Plus, it will lead the SQL statement before the comment to be executed twice. For example, the script file “test.sql” includes follow SQL statements:

select 'aaa' from dual;

/*abc*/

select 'bbb' from dual;

We just want the statement ‘select 'aaa' from dual;’ to be executed once. However, we will get another result:

SQL> @c:test.sql

'AA

---

aaa

'AA

---

aaa

'BB

---

bbb

As you can see, the statement were executed twice.

This bug would not impact PL/SQL developer.

And this is the correct script (there is a blank char between ‘/*’ and ‘abc’):

select 'aaa' from dual;

/* abc */

select 'bbb' from dual;

The right result:

SQL> @c:test.sql

'AA

---

aaa

'BB

---

bbb

1.5.2 Commends follow a SQL statement
If a comment follows a SQL statement (the comments including ‘--’ mode and ‘/**/’ mode), this statement will be treated as comments, and will not be executed. For example, here a ‘test.sql’ script:

select 'aaa' from dual; --aaa

select 'bbb' from dual;

You will get this result when execute it:

SQL> @c:test.sql

'BB

---

bbb

Noted, the first SQL statement was not executed, because it was followed by a comments with ‘--’.

And, if the comment was placed in another line follow closely the SQL statement, it will also raise this bug:

select 'aaa' from dual;

--aaa

select 'bbb' from dual;

Execute the script:

SQL> @c:test.sql

'BB

---

bbb

This bug impact both SQL*Plus and PL/SQL developer.

And this is the correct script:

-- aaa

select 'aaa' from dual;

select 'bbb' from dual;

The right result:

SQL> @c:test.sql

'AA

---

aaa

'BB

---

bbb

1.5.3 Commends following a SQL statement, followed by another SQL statement closely
If a commend follows a SQL statement, and it was followed by another SQL statement closely. It will lead to a execution error. For example, this is the script:

select 'aaa' from dual; --aaa

select 'bbb' from dual;

Execute the script:

SQL> @c:test.sql

select 'aaa' from dual; --aaa

*

ERROR at line 1:

ORA-00911: invalid character

This bug will ignore the comments between them. For example, this is the script:

select 'aaa' from dual;--aaa

/* abc */

select 'bbb' from dual;

It will still raise the error:

SQL> @c:test.sql

select 'aaa' from dual;--aaa

*

ERROR at line 1:

ORA-00911: invalid character

This bug impact both SQL*Plus and PL/SQL developer.

And this is the correct script:

-- aaa

select 'aaa' from dual;

select 'bbb' from dual;

The right result:

SQL> @c:test.sql

'AA

---

aaa

'BB

---

bbb