SQL Server queries case sensitivity

Question

I have this database:

abcDEF

ABCdef

abcdef

if I write: select * from MyTbl where A='ABCdef'

how to get: ABCdef

and how to get:

abcDEF

    ABCdef

    abcdef

Thanks in advance

forgot to write - sqlCE

Solution 1

You can make your query case sensitive by making use of the COLLATE keyword.

SELECT A 
FROM MyTbl 
WHERE A COLLATE Latin1_General_CS_AS = 'ABCdef'

Solution 2

If you have abcDEF, ABCdef, abcdef already in the database then it's already case sensitive or you have no constraint.

You'd have to add a COLLATE on both sides to make sure it's truly case sensitive (for a non case sensitive database) which will invalidate index usage

SELECT TheColumn
FROM MyTable 
WHERE TheColumn COLLATE Latin1_General_CS_AS = 'ABCdef' COLLATE Latin1_General_CS_AS

What about accents too? Latin1_General_CS_AI, Latin1_General_Bin?

Solution 3

Try this just add binary keyword after where:

select * from MyTbl where binary A = 'ABCdef';

Solution 4

SQL is non-case-sensitive by default, so you will get all three items if doing a simple string comparison. To make it case-sensitive, you can cast the value of the field and your search value as varbinary:

SELECT * FROM MyTbl WHERE CAST(A AS varbinary(20)) = CAST('ABCdef' as varbinary(20))

The above assumes your varchar field is sized at 20. For nvarchar double it (thanks @ps2goat).

Solution 5

It's all about collation. Each one has a suffix (CI and CS, meaning Case Insensitive, and Case Sensitive).

http://www.databasejournal.com/features/mssql/article.php/10894_3302341_2/SQL-Server-and-Collation.htm

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Comments

[TomTom]

-1 Whow. That is the worst answer possible - take out all indices, force a table scan and totally ignore the reality of being able to change the collation ;)

[Martin Smith]

@TomTom - Using COLLATE means the indices won't be used anyway.

[Josh Anderson]

I'm sure there are worse answers -- that query at least functions. From my understanding there's no way to specify case insensitivity using indexes unless you're doing a binary comparison. I've never tried it, but if your table column was defined as a VARBINARY, you could do an index on that and only have to cast your search string.

[ps2goat]

wouldn't an nvarchar be 40 bytes if it was 20 characters long?