| title | C# Data Types |
|---|---|
| titleSuffix | SQL Server Language Extensions |
| description | Map data types from C# .NET to SQL Server for input and output data structures, and for input parameters on the sp_execute_external_script. |
| author | rwestMSFT |
| ms.author | randolphwest |
| ms.date | 08/28/2025 |
| ms.service | sql |
| ms.subservice | language-extensions |
| ms.topic | conceptual |
| monikerRange | >=sql-server-ver15 || >=sql-server-linux-ver15 |
[!INCLUDE sqlserver2019-and-later]
This article maps SQL Server data types to .NET data types (used by C#) for data structures and parameters on sp_execute_external_script.
The following SQL and .NET data types are currently supported for input/output data sets and input/output parameters.
| SQL Server data type | .NET data type | Comment |
|---|---|---|
| bit | bool |
|
| tinyint | byte |
|
| smallint | short |
|
| int | int |
|
| real | float |
|
| bigint | long |
|
| float | double |
|
| nchar(n) | string |
|
| nvarchar(n) | string |
|
| binary(n) | byte[] |
|
| varbinary(n) | byte[] |
|
| nvarchar(max) | string |
|
| varbinary(max) | byte[] |
|
| uniqueidentifier | Guid |
|
| char(n) | string |
|
| varchar(n) | string |
|
| varchar(max) | string |
|
| date | DateOnly |
.NET 6 and later versions |
| time | TimeOnly |
.NET 6 and later versions |
| numeric | decimal |
|
| decimal | decimal |
|
| money | decimal |
|
| smallmoney | decimal |
|
| smalldatetime | DateTime |
|
| datetime | DateTime |
|
| datetime2 | DateTime |