How to get the size of a varchar[n] field in one SQL statement?

Suppose that I have a SQL table that has a varchar[1000] field called "Remarks".

I would like to craft a single SQL statement, which when executed, will return 1000, or whatever the size of the varchar field might be changed to in the future.

Something like SELECT size(Remarks) FROM mytable.

How do I do this?

Solution 1:

select column_name, data_type, character_maximum_length    
  from information_schema.columns  
 where table_name = 'myTable'

Solution 2:

On SQL Server specifically:

SELECT DATALENGTH(Remarks) AS FIELDSIZE FROM mytable

Documentation

Solution 3:

For SQL Server (2008 and above):

SELECT COLUMNPROPERTY(OBJECT_ID('mytable'), 'Remarks', 'PRECISION');

COLUMNPROPERTY returns information for a column or parameter (id, column/parameter, property). The PRECISION property returns the length of the data type of the column or parameter.

COLUMNPROPERTY documentation