In simple word we can say sql server string comparison is case sensitive
If we will compare the strings in sql sever in where clause either using equal to (=) operator or like operator case sensitiveness will depend upon default collation of your database. That is if your collation is case sensitive then comparison will case sensitive and if collation is case insensitive then comparator will not case sensitive.
In sql sever default case default collation is SQL_Latin1_General_CP1_CI_AS. It case insensitive (CI) and ascent sensitive (AS)
DECLARE @Str AS VARCHAR(20) = 'ExactHelp'
IF @Str = 'exacthelp'
SELECT 'Case insensative'
ELSE
SELECT 'Case sensative'
Output: Case insensitive
Sql query to know default collation name of your database name:
SELECT DATABASEPROPERTYEX('Database_Name', 'Collation')
Example of case sensitive comparison in sql sever:
DECLARE @Str AS VARCHAR(20) = 'ExactHelp'
IF @Str = 'exacthelp' COLLATE SQL_Latin1_General_CP1_CS_AS
SELECT 'Case insensitive'
ELSE
SELECT 'Case sensitive'
Output: Case sensitive
Note:
SQL_Latin1_General_CP1_CS_AS is case sensitive (CS) as well as ascent sensitive (AS) collation.