Stored Procedures: Delimiter

[Silver]

In the book a stored procedure's DELIMITER and END both end with double dollar signs ($$), in some other sources I found them ending with double forward slashes (//). Are there any other signs/characters used for same? I also presume that such signs and characters have no inherent differences in what the stored procedure does. If there is any difference pertaining to the type of charcters/signs used after DELIMITER and END, we would appreciate knowing it.

[HartleySan]

I think Larry mentions that the delimiter has to be changed to avoid the meaning of the semicolon being doubled-up and confused by the SQL parser. As such, I think any delimiter that doesn't cause confusion is fine.

[Silver]

Thanks HartleySan. Since $$ and // are doing the job, they are certainly fine, however, I wanted to know if any other characters or signs besides $$, // could be used for the same purpose, and if there are any pros or cons or other differences in using $$ over //. This is simply not about why we use $$, //, but rather about whether or not there are differences in their usage. To give an example: both 'include' and 'require' do the same job (including a file into another), however, there is a difference when one is used over the other.

[Larry]

You may be missing the point of the delimiter. Literally ANY character or character combination can be used. There is absolutely no difference in the usage between $$ and // or ?? or XY or whatever. It's just a two-character combination used to mark the end of a complete SQL command. The default delimiter is the semicolon. The delimiter gets changed for defining stored procedures so that the default semicolon does not pre-emptively end the command. You can use literally anything for a replacement delimiter with equal effectiveness. The only rule is to use something that wouldn't appear within the command itself, such as the semicolon, the asterisk, a comma, the letter F, and so forth.