How to convert a column value from one data type to another in SQL Server?

Updated on September 22, 2015     Kisan Patel

This tutorial will show you how to convert a column value from one data type to another in SQL Server?
To convert a column value from one data type to another, we use CONVERT function. This accepts
three parameters

•  The target data type to convert to
• The value to convert to
• The style number to convert to (optional)

The main difference between CAST and CONVERT is that CONVERT after converting the data type,
also apply the formatting number based on value we pass.
SELECT
Convert(varchar(20), GETDATE()) DefaultFormat,
Convert(varchar(20), GETDATE(), 101) DDMMYYYY,
Convert(varchar(20), GETDATE(), 102) YYYYMMDD,
Convert(varchar(20), GETDATE(), 103) DDMMYYYY,
Convert(varchar(20), GETDATE(), 104)
SELECT Convert(varchar(20), GETDATE(), 105),
Convert(varchar(20), GETDATE(), 106),
Convert(varchar(20), GETDATE(), 107)
SELECT Convert(varchar(20), GETDATE(), 108),
Convert(varchar(20), GETDATE(), 109),
Convert(varchar(20), GETDATE(), 110)
SELECT Convert(varchar(20), GETDATE(), 111),
Convert(varchar(20), GETDATE(), 112),
Convert(varchar(20), GETDATE(), 113),
Convert(varchar(20), GETDATE(), 114)
Notice the 3rd parameter of each CONVERT function and notice the result below.