The SQL
DISTINCT clause isn't case sensitive, which means that your query might end up pulling records with different cases.
A simple fix for this is to use the COLLATE clause in conjunction with the DISTINCT clause.
Use sql_latin1_general_cp1_ci_ai for case sensitive distinct clause:
a) CASE INSENSITIVE DISTINCT CLAUSE
SELECT DISTINCT (Item) COLLATE sql_latin1_general_cp1_cs_as
FROM (
SELECT 'a' item
UNION ALL SELECT 'A'
)items
b) CASE SENSITIVE DISTINCT CLAUSE
SELECT DISTINCT (Item) COLLATE sql_latin1_general_cp1_ci_ai
FROM (
SELECT 'a' item
UNION ALL SELECT 'A'
) items
