SQL Batch Queries in SQL Server 2022

SQL Batch Queries refer to groups of one or more Transact-SQL (T-SQL) statements that are sent to and executed by SQL Server as a single unit. In SQL Server 2022, batch processing remains a fundamental concept for query execution and optimization.
Key Characteristics of SQL Batch Queries

1. Definition:
   • A batch is a set of SQL statements submitted together and parsed/executed as a unit
   • Batches are separated by the GO statement in tools like SSMS (though GO is not a T-SQL command)
2. Execution Context:
   • Each batch runs in a single execution context
   • Variables declared in one batch aren't visible to subsequent batches
   • Errors may affect batch execution differently depending on severity

SQL Server 2022 Enhancements for Batch Processing

1. Intelligent Query Processing (IQP) Improvements:
   • Enhanced batch mode memory grant feedback
   • Improved batch mode adaptive joins
   • Degree of Parallelism (DOP) feedback for batch mode operations
2. Parameter Sensitive Plan (PSP) Optimization:
   • Better handling of batches with parameterized queries that have varying cardinality
3. Memory-Optimized TempDB Metadata:
   • Improved performance for batches that heavily use temporary tables

-- Batch 1: Creates a table and inserts data
CREATE TABLE dbo.Customers (
    CustomerID INT PRIMARY KEY,
    Name NVARCHAR(100)
);
INSERT INTO dbo.Customers VALUES (1, 'John Doe');
GO  -- Signals end of batch

-- Batch 2: Queries the table (can't see variables from Batch 1)
SELECT * FROM dbo.Customers;
GO

Best Practices for Batch Queries in SQL Server 2022

1. Transaction Management:
   • Group related operations in the same batch when they should succeed or fail together
   • Be aware that batches don't automatically imply transactions
2. Error Handling:
   • Use TRY/CATCH blocks within batches for comprehensive error handling
   • Understand that compilation errors prevent the entire batch from executing
3. Performance Considerations:
   • Large batches can reduce network round trips but may increase memory usage
   • Consider using table-valued parameters for batch data operations
   • Leverage batch mode execution for analytical workloads
4. Security:
   • Use parameterized batches to prevent SQL injection
   • Consider the EXECUTE AS clause for specific permission contexts

Batch vs. Transaction Important distinction:

• Batch: A group of statements sent to the server together
• Transaction: A logical unit of work that must be completed as a whole (using BEGIN TRANSACTION, COMMIT, ROLLBACK)

To send SQL batch^[1] statements all at once for execution in SQL Server Management Studio (SSMS), you can follow these steps:
✅ What is a SQL Batch Statement?
A batch is a group of one or more T-SQL statements sent to SQL Server for execution as a unit. Batches are separated by the `GO` keyword in SSMS.
🧭 Steps to Execute SQL Batch Statements in SSMS

1. Open SSMS and Connect to a Server
   • Launch SSMS
   • Connect to your SQL Server 2022 instance
2. Open a New Query Window
   • Click New Query in the toolbar
   • Make sure the correct database is selected from the dropdown
3. Enter Your SQL Batch Script

   
   USE AdventureWorks2022;
   GO
   
   CREATE TABLE dbo.TestBatch (
        ID INT PRIMARY KEY,
        Name NVARCHAR(50)
   );
   GO
   
   INSERT INTO dbo.TestBatch (ID, Name)
   VALUES (1, 'Thomas'), (2, 'Anna');
   GO
   
   SELECT * FROM dbo.TestBatch;
   GO
       
   

   • Each section of code between GO is treated as a batch
4. Execute All Batches at Once
   • Click the Execute button or press F5
   • SSMS will send each batch to SQL Server sequentially

• GO is not a T-SQL command; it’s a batch separator understood by SSMS and sqlcmd, but not SQL Server itself
• You cannot use GO inside stored procedures or functions
• All batches are executed in sequence, not in parallel

🧰 Bonus Tip (Automated Batch Execution)
You can also execute a `.sql` script file containing multiple batches using the `sqlcmd` utility:

sqlcmd -S localhost -d AdventureWorks2022 -i C:\path\to\batch-script.sql

A batch is a group of one or more Transact-SQL (T-SQL) statements that are submitted together to SQL Server for execution. If there are no `GO` keywords in a set of statements, they are all considered to be in a single batch.
✅ Advantages of Using Batches
If a syntax or compile-time error occurs in a batch, SQL Server may stop executing the remaining statements in that batch. This can be helpful during troubleshooting because it isolates the problematic code. However, runtime errors (such as divide-by-zero or constraint violations) may allow the batch to continue unless explicitly handled.
🔁 Variables and Batches
Each batch is treated as a separate compilation unit. Therefore:

• Any variables (DECLARE @var INT, etc.) used in a batch must be declared within that batch.
• Variables do not carry over across batches unless passed via a stored procedure or function.

⚠️ When Not to Use Batching with Other Statements
The following `CREATE` statements must be executed as single-statement batches (i.e., no other SQL statements can appear in the same batch):

• CREATE PROCEDURE
• CREATE TRIGGER
• CREATE VIEW
• CREATE DEFAULT
• CREATE RULE

This is because SQL Server requires these definitions to be compiled in isolation from other statements.
🔧 How to Create a Batch: Using the `GO` Statement
The `GO` statement is not a T-SQL command, but rather a batch separator understood by SSMS, `sqlcmd`, and other tools. All statements between two `GO` commands form one batch. If no `GO` keyword is used, all statements in the query editor are submitted as one batch. Think of there being an implicit `GO` at the end of your submission.
🧪 Examples
Single Batch (No GO) : The following is treated as one batch:

UPDATE Employees
SET FirstName = 'Anthony',
    LastName = 'Mann'
WHERE EmployeeID = 101;

SELECT *
FROM Employees
WHERE EmployeeID = 101;

Multiple Batches (Using GO):

USE Timesheets;
GO

UPDATE Employees
SET FirstName = 'Anthony',
    LastName = 'Mann'
WHERE EmployeeID = 101;

SELECT *
FROM Employees
WHERE EmployeeID = 101;

In this example:

• The first USE statement is one batch.
• The UPDATE and SELECT are part of the second batch.

[1]Batch: A set of Transact-SQL commands that are sent to the SQL Server engine, all at one time. Batches are separated by GO keywords.