How to Perform Case-Insensitive String Comparisons in PostgreSQL?

Case Insensitive String Comparison in PostgreSQL

In PostgreSQL, performing case-insensitive string comparisons can be essential for many scenarios. While the like and ilike operators are available for single values, they do not extend to sets.

To address this limitation, PostgreSQL provides the following options for case-insensitive string comparisons:

1. Using the ilike Operator:

The ilike operator is similar to like, but it performs case-insensitive comparisons. It can be used as follows:

select *
where email ilike '[email protected]'

2. Escaping Special Characters:

When using the ilike operator with special characters in your strings, it is essential to escape them correctly. You can achieve this using the replace() function:

where email ilike replace(replace(replace(, '~', '~~'), '%', '~%'), '_', '~_') escape '~'

Alternatively, you can create a custom function to escape text.

3. Comparing Against Arrays:

If you need to compare against an array of strings, you can use the any operator:

where email ilike any(array['[email protected]', '[email protected]'])

By utilizing these techniques, you can effectively perform case-insensitive string comparisons in PostgreSQL for both single values and sets of values.

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