Searching For Valid Characters For T-SQL Regular Identifiers

Kevin Feasel

2018-04-04

T-SQL

Solomon Rutzky is on a mission to find a national treasure:

Quite often these types of things are not that easy. Yes, it is very tempting to assume that the limited test is good enough and that we did indeed find the exact list of characters (plus we would need to add in the four extra characters: at sign (@), dollar sign ($), number sign (#), and underscore (_)). However, based on my experiences, it seems that more often than not, doing an exhaustive test results in a slightly different answer that invalidates the previous conclusion (which was based on the limited test). So, while it does take more time to do more extensive testing, it seems like we have little choice if we truly want to know how these things actually work.

What that means is, at the very least, we need to get the complete list of characters accepted by SQL Server for non-delimited identifiers to make sure that the totals match the number of code points returned by the searches done in Step 1.

This post is an interesting dive into the oddities of Unicode, but leaves us on a cliffhanger.  Also, full-crazy Nicolas Cage beats mullet-wearing Tom Hanks any day.

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