Change the data type of a column in a table

To change the data type of a column in a table, use the following syntax:

ALTER TABLE table_name
ALTER COLUMN column_name datatype

In this blog post, we will see how to change the datatypes of the column with an example.

We will create a sample table and change the column datatypes.

USE XYZDb
GO

CREATE TABLE dbo.SampleTable
(
   ID INT, 
   FirstCol VARCHAR(10), 
   SecondCol DATETIME
)
GO

ALTER TABLE dbo.SampleTable
ALTER COLUMN ID VARCHAR(100)
GO

ALTER TABLE dbo.SampleTable
ALTER COLUMN FirstCol VARCHAR(100)
GO

ALTER TABLE dbo.SampleTable
ALTER COLUMN SecondCol VARCHAR(100)
GO

That's it.. Your column datatypes are changed...