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Transact-SQL Syntax Conventions (Transact-SQL)

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


Used for


Transact-SQL keywords.


User-supplied parameters of Transact-SQL syntax.


Database names, table names, column names, index names, stored procedures, utilities, data type names, and text that must be typed exactly as shown.


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.


Indicates the preceding item can be repeated n number of times. The occurrences are separated by commas.


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:


| database_name**.[schema_name].**object_name

| schema_name**.**object_name

| object_name

  • server_name
    Specifies a linked server name or remote server name.

  • database_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.

  • schema_name
    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. For more information about schemas, see User-Schema Separation.

  • object_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



Four-part name.


Schema name is omitted.


Database name is omitted.


Database and schema name are omitted.


Server name is omitted.


Server and schema name are omitted.


Server and database name are omitted.


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. For more information, see Server-Side Programming with Unicode.