SQL server determines case sensitivity by COLLATION.

COLLATION can be set at various levels.

Server-level

Database-level

Column-level

Expression-level

Here is the MSDN reference--https://msdn.microsoft.com/en-us/library/ms143726.aspx

Check Server Collation--

SELECT SERVERPROPERTY('COLLATION')

Check Database Collation--

SELECT DATABASEPROPERTYEX('AdventureWorks', 'Collation') SQLCollation;

Check Column Collation

select table_name, column_name, collation_name

from...