SQL String Comparison: When to Use '=' vs. 'LIKE'?

Comparing Strings in SQL: '=' vs. 'LIKE'

The ongoing debate between using '=' and 'LIKE' for string comparisons in SQL stems from their distinct functionality.

Reasons to Use 'LIKE':

• Wildcard Search: 'LIKE' allows for flexible matching using wildcards such as '%' (any number of characters) and '_' (any single character). This is useful for finding partial matches or patterns within strings.

SELECT * FROM user WHERE login LIKE '%Test%';

Results:

• TestUser1
• TestUser2
• TestU
• Test

Reasons to Use '=':

• Exact Match: '=' performs an exact comparison between two strings. It ensures that the specified values are identical character by character.
• Faster Execution: Exact match queries using '=' are significantly faster than wildcard searches using 'LIKE'.

Performance and Readability:

Performance-wise, '=' is the preferred choice for exact matches as it uses a more efficient optimization path in SQL databases. 'LIKE' requires additional processing for pattern matching, which can impact performance for large datasets.

In terms of readability, both 'LIKE' and '=' are clear and concise. However, using 'LIKE' for exact matches may introduce potential confusion as it suggests wildcard searching when it's not intended.

The above is the detailed content of SQL String Comparison: When to Use '=' vs. 'LIKE'?. For more information, please follow other related articles on the PHP Chinese website!