When should I use semicolons in SQL Server?

According to [Transact-SQL Syntax Conventions (Transact-SQL)][1] (MSDN)

> Transact-SQL statement terminator. Although the semicolon is not required for most statements in this version of SQL Server, it will be required in a future version.

(also see @gerryLowry 's comment)

[1]:

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If you like getting random *Command Timeout* errors in SQLServer then leave off the semi-colon at the end of your CommandText strings.

I don't know if this is documented anywhere or if it is a bug, but it does happen and I have learnt this from bitter experience.

I have verifiable and reproducible examples using SQLServer 2008.

aka -> *In practice, always include the terminator even if you're just sending one statement to the database.*

It appears that semicolons should not be used in conjunction with cursor operations: `OPEN`, `FETCH`, `CLOSE` and `DEALLOCATE`. I just wasted a couple of hours with this. I had a close look at the BOL and noticed that [;] is not shown in the syntax for these cursor statements!!

So I had:

OPEN mycursor;

and this gave me error 16916.

But:

OPEN mycursor

worked.

You **must** use it.

> The practice of using a semicolon to terminate statements is standard and in fact is a requirement
in several other database platforms. SQL Server requires the semicolon only in particular
cases—but in cases where a semicolon is not required, using one doesn’t cause problems.
I strongly recommend that you adopt the practice of terminating all statements with a semicolon.
Not only will doing this improve the readability of your code, but in some cases it can
save you some grief. (When a semicolon is required and is not specified, the error message SQL
Server produces is not always very clear.)

And most important:

> The SQL Server documentation indicates that not terminating T-SQL statements with
a semicolon is a deprecated feature. This means that the long-term goal is to enforce use
of the semicolon in a future version of the product. That’s one more reason to get into the
habit of terminating all of your statements, even where it’s currently not required.

Source: *Microsoft SQL Server 2012 T-SQL Fundamentals* by Itzik Ben-Gan.


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An example of why you always must use `;` are the following two queries (copied from this [post][1]):

BEGIN TRY
BEGIN TRAN
SELECT 1/0 AS CauseAnException
COMMIT
END TRY
BEGIN CATCH
SELECT ERROR_MESSAGE()
THROW
END CATCH

![enter image description here][2]

BEGIN TRY
BEGIN TRAN
SELECT 1/0 AS CauseAnException;
COMMIT
END TRY
BEGIN CATCH
SELECT ERROR_MESSAGE();
THROW
END CATCH

![enter image description here][3]


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[2]:

[3]: