About-R_DataTypeConversionToSqlServer

Data Type Conversion between R and SQL Server

The following table shows the changes in data types and values when data from SQL Server is used in an R script and then returned to SQL Server.

SQL Server type	R class	Type in RESULT SET	Comments
smalldatetime	POSIXct	datetime	Represented as GMT
smallmoney	numeric	float
datetime	POSIXct	datetime	Represented as GMT
money	numeric	float
uniqueidentifier	character	varchar(max)
numeric(p,s)	numeric	float
decimal(p,s)	numeric	float
date	POSIXct	datetime	Represented as GMT
tinyint	integer	int
bit	logical	bit
smallint	integer	int
int	integer	int
float	numeric	float
real	numeric	float
bigint	numeric	float
binary(n) n <= 8000	raw	varbinary(max)	Only allowed as input parameter and output
char(n) n <= 8000	character	varchar(max)
varbinary(n) n <= 8000	raw	varbinary(max)	Only allowed as input parameter and output
varchar(n) n <= 8000	character	varchar(max)
varbinary(max)	raw	varbinary(max)	Only allowed as input parameter and output

https://msdn.microsoft.com/en-us/library/mt590948.aspx