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SQL Expressions

A Review of Built-Functions


Converting a Value



Like CAST(), the CONVERT() function is used to convert a value. Unlike CAST(), CONVERT can be used to convert a value its original type into a non-similar type. For example, you can use CONVERT to cast a number into a string and vice-versa.

The syntax of the CONVERT() function is:

CONVERT(DataType [ ( length ) ] , Expression [ , style ])
The first argument must be a known data type, such as those we reviewed in Lesson 4. If you are converting the value into a string (varchar, nvarchar, char, nchar) or a binary type, you should specify the number of allowed characters the data type's own parentheses. As reviewed for the CAST() function, the Expression is the value that needs to be converted.

Here is an example:

-- Square Calculation
DECLARE @Side As Decimal(10,3),
@Perimeter As Decimal(10,3),
@Area As Decimal(10,3);
SET @Side = 48.126;
SET @Perimeter = @Side * 4;
SET @Area = @Side * @Side;
PRINT 'Square Characteristics';
PRINT '-----------------------';
PRINT 'Side = ' + CONVERT(varchar(10), @Side, 10);
PRINT 'Perimeter = ' + CONVERT(varchar(10), @Perimeter, 10);
PRINT 'Area = ' + CONVERT(varchar(10), @Area, 10);
GO






source : http://blogs.msdn.com/sharepoint/default.aspx