Should you choose the MONEY or DECIMAL(x,y) datatypes in SQL Server?

Question

I\'m curious as to whether or not there is a real difference between the money datatype and something like decimal(19,4) (which is what money uses

Answer 1

As a counter point to the general thrust of the other answers. See The Many Benefits of Money…Data Type! in SQLCAT's Guide to Relational Engine

Specifically I would point out the following

Working on customer implementations, we found some interesting performance numbers concerning the money data type. For example, when Analysis Services was set to the currency data type (from double) to match the SQL Server money data type, there was a 13% improvement in processing speed (rows/sec). To get faster performance within SQL Server Integration Services (SSIS) to load 1.18 TB in under thirty minutes, as noted in SSIS 2008 - world record ETL performance, it was observed that changing the four decimal(9,2) columns with a size of 5 bytes in the TPC-H LINEITEM table to money (8 bytes) improved bulk inserting speed by 20% ... The reason for the performance improvement is because of SQL Server’s Tabular Data Stream (TDS) protocol, which has the key design principle to transfer data in compact binary form and as close as possible to the internal storage format of SQL Server. Empirically, this was observed during the SSIS 2008 - world record ETL performance test using Kernrate; the protocol dropped significantly when the data type was switched to money from decimal. This makes the transfer of data as efficient as possible. A complex data type needs additional parsing and CPU cycles to handle than a fixed-width type.

So the answer to the question is "it depends". You need to be more careful with certain arithmetical operations to preserve precision but you may find that performance considerations make this worthwhile.