Koen Verbeeck (2/14/2012)
kll 51891 (2/14/2012)
I would have expected it to fail due to no newline or semicolon.
But it were not so
Anywhere I can find specific rules about when to use and when not to use semicolon?
Except the reserved word ";with" of course.
The semicolon is not yet obligated, except when using the WITH clause. This probably will change in a future version.
If there's a statement before the WITH clause, it should be terminated with a semicolon. Pay attention, this is not the same as saying that it should be ";WITH". If everyone starts terminating statements with semicolon in old code to make the code portable to a newer edition of SQL Server, all ;WITH statements will fail.
Most of the above is true.
Terminiating SQL statements with a semicolon has always been allowed in SQL Server, but it was optional. WITH was the first keyword (but is not the only one) that requires the statement before it (if any) to be semicolon-terminated, otherwise the parser would think that the WITH keyword was for query hints. It has already been announced that in some future version, omitting the semicolon will be disallowed in all cases. There has not been any mention as to which version that will be. But it's a good idea to start getting into the habit now of always using the semicolon statement terminator.
I consider the use of ;WITH a bad habit, as it works around one limitation while not addressing the true underlying issue. And it will come back to bite you when terminating is no longer optional. However, it does currently work - not because he parser accepts prepending WITH with a semicolon as a viable alternative, but because the parser ignores whitespace and line breaks - so it "sees" the semicolon right after the end of the preceding statement and interprets it as a statement terminator.
However, it is not true that ;WITH will cause errors when all statements are semicolon terminated. There is no limit to how many semicolons you use and where you place them. The code below, though clearly not recommended coding style, works.
;;;WITH x AS (SELECT 1 AS a)
SELECT * FROM x