Is SQL Server's LIKE Operator Case-Sensitive, and How Does Collation Affect It?

SQL Server's LIKE Operator: Case Sensitivity Explained

SQL Server's LIKE operator provides robust string matching. However, its case sensitivity isn't inherent to the operator itself. Instead, it's determined by the column's collation.

Collation: The Key to Case Sensitivity

A column's collation dictates how character comparisons are handled. SQL Server supports various collations, each specifying the character set, alphabet, and crucially, case-sensitivity rules.

Determining Collation

To check a database's collation:

<code class="language-sql">SELECT DATABASEPROPERTYEX('databasename', 'collation') AS SQLCollation;</code>

For a specific column:

<code class="language-sql">SELECT COLLATION_NAME
FROM sys.columns
WHERE object_id = OBJECT_ID('TableName') AND name = 'ColumnName';</code>

Collation's Impact on LIKE Results

Different collations produce different LIKE results. For example:

• sql_latin1_general_cp1_ci_as: Case-insensitive, accent-sensitive.
• sql_latin1_general_cp1_cs_as: Case-sensitive, accent-sensitive.

Modifying Collation (Use with Caution)

While generally discouraged, you can alter a column's collation:

<code class="language-sql">ALTER TABLE TableName ALTER COLUMN ColumnName VARCHAR(10) COLLATE new_collation;</code>

Alternatively, you can temporarily override case sensitivity within a query (not recommended for production):

<code class="language-sql">SELECT column1 COLLATE sql_latin1_general_cp1_ci_as AS column1
FROM table1;</code>

In Summary

Accurate string matching with SQL Server's LIKE operator hinges on understanding the impact of collation. Careful collation selection ensures queries behave as expected, regardless of case sensitivity requirements.

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