Transact-SQL Syntax Conventions (Transact-SQL)

APPLIES TO: yesSQL Server (starting with 2008) yesAzure SQL Database yesAzure SQL Data Warehouse yesParallel Data Warehouse

The following table lists and describes conventions that are used in the syntax diagrams in the Transact-SQL Reference.

Convention Used for
UPPERCASE Transact-SQL keywords.
italic User-supplied parameters of Transact-SQL syntax.
bold Database names, table names, column names, index names, stored procedures, utilities, data type names, and text that must be typed exactly as shown.
underline Indicates the default value applied when the clause that contains the underlined value is omitted from the statement.
| (vertical bar) Separates syntax items enclosed in brackets or braces. You can use only one of the items.
[ ] (brackets) Optional syntax items. Do not type the brackets.
{ } (braces) Required syntax items. Do not type the braces.
[,...n] Indicates the preceding item can be repeated n number of times. The occurrences are separated by commas.
[...n] Indicates the preceding item can be repeated n number of times. The occurrences are separated by blanks.
; 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.
<label> ::= The name for a block of syntax. This convention is used to group and label sections of lengthy syntax or a unit of syntax that can be used in more than one location within a statement. Each location in which the block of syntax can be used is indicated with the label enclosed in chevrons: <label>.

A set is a collection of expressions, for example <grouping set>; and a list is a collection of sets, for example <composite element list>.

Multipart Names

Unless specified otherwise, all Transact-SQL references to the name of a database object can be a four-part name in the following form:

server_name .[database_name].[schema_name].object_name

| database_name.[schema_name].object_name

| schema_name.object_name

| object_name

Specifies a linked server name or remote server name.

Specifies the name of a SQL Server database when the object resides in a local instance of SQL Server. When the object is in a linked server, database_name specifies an OLE DB catalog.

Specifies the name of the schema that contains the object if the object is in a SQL Server database. When the object is in a linked server, schema_name specifies an OLE DB schema name.

Refers to the name of the object.

When referencing a specific object, you do not always have to specify the server, database, and schema for the SQL Server Database Engine to identify the object. However, if the object cannot be found, an error is returned.


To avoid name resolution errors, we recommend specifying the schema name whenever you specify a schema-scoped object.

To omit intermediate nodes, use periods to indicate these positions. The following table shows the valid formats of object names.

Object reference format Description
server . database . schema . object Four-part name.
server . database .. object Schema name is omitted.
server .. schema . object Database name is omitted.
server ... object Database and schema name are omitted.
database . schema . object Server name is omitted.
database .. object Server and schema name are omitted.
schema . object Server and database name are omitted.
object Server, database, and schema name are omitted.

Code Example Conventions

Unless stated otherwise, the examples provided in the Transact-SQL Reference were tested by using SQL Server Management Studio and its default settings for the following options:


Most code examples in the Transact-SQL Reference have been tested on servers that are running a case-sensitive sort order. The test servers were typically running the ANSI/ISO 1252 code page.

Many code examples prefix Unicode character string constants with the letter N. Without the N prefix, the string is converted to the default code page of the database. This default code page may not recognize certain characters.

"Applies to" References

The Transact-SQL reference includes articles related to SQL Server ( SQL Server 2008 through SQL Server 2017), Azure SQL Database, and Azure SQL Data Warehouse.

Near the top of each article is a section indicating which products support the subject of the article. If a product is omitted, then the feature described by the article is not available in that product. For example, availability groups were introduced in SQL Server 2012 (11.x). The CREATE AVAILABILITY GROUP article indicates it applies to SQL Server ( SQL Server 2012 (11.x) through SQL Server 2017) because it does not apply to SQL Server 2008, SQL Server 2008 R2, or Azure SQL Database.

In some cases, the general subject of the article can be used in a product, but all of the arguments are not supported. For example, contained database users were introduced in SQL Server 2012 (11.x). The CREATE USER statement can be used in any SQL Server product, however the WITH PASSWORD syntax cannot be used with older versions. In this case, additional Applies to sections are inserted into the appropriate argument descriptions in the body of the article.

See Also

Transact-SQL Reference (Database Engine)
Reserved Keywords (Transact SQL)
Transact-SQL Design Issues
Transact-SQL Naming Issues
Transact-SQL Performance Issues