How to perform a case sensitive search in WHERE clause using SQL Server?

How to embrace case sensitivity in SQL Server

Every column in a SQL Server query lets you apply COLLATE clause, which means you instruct your database to follow a case-sensitive comparison.

Different methods of implementing case sensitivity

Sure, the COLLATE clause is a go-to method, but SQL Server provides other ways too. One option is to use the CAST function, converting the column to VARBINARY, leading to a case-sensitive comparison:

-- When you want to step up your matching game
SELECT * 
FROM your_table
WHERE CAST(your_column AS VARBINARY) = CAST('CaseSensitiveValue' AS VARBINARY)
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Another approach is to use the BINARY_CHECKSUM function. It provides a byte-by-byte comparison:

-- BINARY_CHECKSUM? More like "rockstar" of case-sensitive matching
SELECT * 
FROM your_table
WHERE BINARY_CHECKSUM(your_column) = BINARY_CHECKSUM('CaseSensitiveValue')


Performance implications with case sensitivity

Enforcing case sensitivity will impact performance to some degree, especially if your indexes are not structured to handle binary collation. Hence, it’s crucial to evaluate different methods and identify the most performant for your use case.

Striking a balance between ease-of-use and precision

While accuracy is a priority in searches, the implementation should be straightforward. Using COLLATE is an easy method and doesn’t cause lasting schema changes, unlike altering table settings.

Digging into technical insights

How to set column-level case sensitivity

For enforcing case sensitivity at the column level, SQL Server allows you to set a specific collation during table creation or alteration:

-- Like a bespoke suit for your column, tailored for case-sensitivity
ALTER TABLE your_table
ALTER COLUMN your_column VARCHAR(255) COLLATE Latin1_General_BIN
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Efficiency with indexes

To make your queries run faster, you can create indexes that correspond with your case-sensitive requirements:

-- When your query needs that extra speed boost
CREATE INDEX idx_your_column_cs ON your_table(your_column COLLATE Latin1_General_BIN)
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The importance of practicing

Dabble with the various methods and apply them to actual scenarios to understand the behavior of each potential solution fully.