70-461 Training Kit Chapter 2, Lesson 2: Data Type Precedence & Data Conversion

Here's the note for data conversion and data type precedence in SQL Server, part of 70-461 exam training kit, chapter 2.

Data Conversion

SQL Server often cast data type with lower precedence to a data type with higher precedence.

Example:  2 + '2' = 4 because '2' is converted to an integer. Since an INT data type has higher precedence than a CHAR.

Data Type Precedence of some data type

User-defined (highest)

Xml

Datetime2

Datetime

Smalldatetime

Date

Time

Float

Real

Decimal

Money

Smallmoney

Bigint

Int

Smallint

Tinyint

Bit

Timestamp

Uniqueidentifier

Nvarchar

Nchar

Varchar

Char

Varbinary

Binary (lowest)

BOL Data type Precedence: http://msdn.microsoft.com/en-us/library/ms190309.aspx

Microsoft 70-461 Training Kit