Transact-SQL Reference - Statements

This section provides a comprehensive reference for Transact-SQL (T-SQL) statements used in Microsoft SQL Server. T-SQL is an extension of SQL that adds procedural programming, local variables, character and time string functions, decision-making, and support for traditional programming constructs. Mastering T-SQL is essential for effectively managing and querying SQL Server databases.

Core T-SQL Statement Categories

T-SQL statements can be broadly categorized based on their function:

• Data Definition Language (DDL) Statements

  Used to define, alter, and drop database objects such as tables, views, indexes, and stored procedures.

• Data Manipulation Language (DML) Statements

  Used to retrieve, insert, update, and delete data in database tables.

• Control-of-Flow Language Statements

  Enable the creation of procedural logic within T-SQL, including conditional execution and loops.

• Security Statements

  Manage permissions, logins, and security contexts within SQL Server.

• Transaction Control Language (TCL) Statements

  Manage transactions, ensuring data consistency and integrity.

Key T-SQL Statements

Here are some of the most frequently used and important T-SQL statements:

• CREATE TABLE

  Defines a new table in the database.

• SELECT

  Retrieves rows from one or more tables.

• INSERT INTO

  Adds new rows to a table.

• UPDATE

  Modifies existing rows in a table.

• DELETE FROM

  Removes rows from a table.

• ALTER TABLE

  Modifies the structure of an existing table.

• DROP TABLE

  Deletes a table from the database.

• BEGIN TRANSACTION

  Starts a transaction.

• COMMIT TRANSACTION

  Saves all changes made during the current transaction.

• ROLLBACK TRANSACTION

  Discards all changes made during the current transaction.

• IF...ELSE

  Executes a set of T-SQL statements based on a specified condition.

• WHILE

  Executes a set of T-SQL statements as long as a specified condition is true.

Further Resources

Explore the links below for more detailed information and examples:

• Transact-SQL Syntax Conventions
• T-SQL Functions Reference
• System Stored Procedures