Here is the script to rename an SQL column,

EXEC sp_rename
@objname = 'table_name.old_column_name',
@newname = 'new_column_name',
@objtype = 'COLUMN'

This is how you can user select case in sql statements,

USE AdventureWorks;
GO
SELECT   ProductNumber, Category =
CASE ProductLine
WHEN 'R' THEN 'Road'
WHEN 'M' THEN 'Mountain'
WHEN 'T' THEN 'Touring'
WHEN 'S' THEN 'Other sale items'
ELSE 'Not for sale'
END,
Name
FROM Production.Product
ORDER BY ProductNumber;
GO

USE AdventureWorks;
GO
SELECT   ProductNumber, Name, 'Price Range' =
CASE
WHEN ListPrice =  0 THEN 'Mfg item - not for resale'
WHEN ListPrice < 50 THEN 'Under $50'
WHEN ListPrice >= 50 and ListPrice < 250 THEN 'Under $250'
WHEN ListPrice >= 250 and ListPrice < 1000 THEN 'Under $1000'
ELSE 'Over $1000'
END
FROM Production.Product
ORDER BY ProductNumber ;
GO

this is similar to if condition that you use in any other programming language but this you can use within a query to check the value and perform the respective task.