In SQL Server, when should you use GO and when should you use semi-colon ;?

sql

sql-best-practices

sql-syntax

sql-performance

byAnton Shumikhin·Dec 15, 2024

GO is essentially a signal to the SQL Server Management Studio (SSMS) to dispatch the prior batch of T-SQL commands for execution. Importantly, it's not part of T-SQL, but a standalone command recognized by SSMS and some other query tools. Conversely, ; is the T-SQL statement terminator. While it may seem optional, it's crucial for preventing syntactic ambiguities and required in front of Common Table Expressions (CTEs).

Example:

-- Define procedure in its own batch, 'cause it likes being independent
CREATE PROCEDURE ResetTable
AS
    TRUNCATE TABLE Employee;
GO -- Execute and end this batch, onwards to glory!

-- Next batch commences here, previous temp tables and variables can't sit with us
SET NOCOUNT ON;

-- CTE requires a preceding semicolon to work with
;WITH Archived AS (
    SELECT * FROM EmployeeArchive
)
SELECT * FROM Archived;

Key Points:

GO: Aids in managing scope, execution, and procedure within a batch.
;: Enhances statement clarity, and is a steady mate for syntax accuracy, especially with CTEs.
Both these elements are like your closet organizers; they keep your code neat and the clutter at bay.

The lowdown on GO and semicolon

Commanding with "GO"

Batch dominion: GO can be your stalwart companion when your commands hinge on each other's successful execution.
Scope management: GO helps isolate each batch's 'variables and temp tables', in its realm, ensuring previous declarations don't haunt.
Tidiness: DDL generators which craft object creation scripts cherish GO for keeping things in order.

Navigate eficiently with ";"

Clarity: A ; punctuates T-SQL statements, offering a reader-friendly guidepost. It's like breadcrumbs Hansel and Gretel left; avoids getting lost.
Standard Accord: Although ; is often optional, including it adheres to SQL's worldwide accepted standard. Elegance, anyone?
Syntax savers: ; plays key roles in CTEs and MERGE statements, healing syntax blues by barring confusion.

Future-proof your SQL Server skills

Evolving syntax rules: To be future-ready, embrace semicolon as an integral part of your SQL writing style. Future SQL Server editions may surprise us!

Scenarios made simpler with ";" and "GO"

Syntax clarity: Semicolons can clear potential confusion in intricate queries with multiple intertwined statements.
Batch partition: GO creates neat segments of batches to prevent CREATE PROCEDURE statements from tripping over incorrect batch placements.
Memory management: Intelligent use of GO in large scripts can aid in memory liberation between batches, fostering enhanced performance.

";" for error-free variable declarations

Adding a ; at the end of variable declarations can evade hazy error messages.

DECLARE @x INT
SET @X = 5; -- No semicolon, SET becomes part of declaration, chaos ensues
PRINT @X;

"GO" for optimal lock and log management

In extensive operations containing multiple DDL and DML statements, GO can be smartly used to release locks and minimize transaction log pressure:

-- Batch to remodel the table, interior decor of sorts
ALTER TABLE Orders ADD LastUpdated DATETIME;
GO -- Locks liberated, deep breaths!

-- Batch to update data, freshness guarantee
UPDATE Orders SET LastUpdated = GETDATE();
GO