How do you change the datatype of a column in SQL Server?

Question

I am trying to change a column from a varchar(50) to a nvarchar(200). What is the SQL command to alter this table?

Answer 1

ALTER TABLE TableName 
ALTER COLUMN ColumnName NVARCHAR(200) [NULL | NOT NULL]

EDIT As noted NULL/NOT NULL should have been specified, see Rob's answer as well.

Answer 2

Don't forget nullability.

ALTER TABLE <schemaName>.<tableName>
ALTER COLUMN <columnName> nvarchar(200) [NULL|NOT NULL]

Answer 3

As long as you're increasing the size of your varchar you're OK. As per the Alter Table reference:

Reducing the precision or scale of a column may cause data truncation.

Answer 4

Try this:

ALTER TABLE "table_name"
MODIFY "column_name" "New Data Type";

Answer 5

Use the Alter table statement.

Alter table TableName Alter Column ColumnName nvarchar(100)

Answer 6

ALTER TABLE [dbo].[TableName]
ALTER COLUMN ColumnName VARCHAR(Max) NULL