C# .NET and SQL Server supported data types

Applies to: SQL Server 2019 (15.x) and later versions

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

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