PostgreSQLdata validation

Check Username Format in PostgreSQL Using Regex

Validate username strings in PostgreSQL using regex operators. SQL query to find usernames with invalid characters or wrong length.

The Regex Pattern

Regex pattern

^[a-zA-Z][a-zA-Z0-9_]{2,19}$

Use this pattern with PostgreSQL's ~ operator.

PostgreSQL SQL Example

-- Query users table in PostgreSQL to find non-conforming usernames using regex operator for format validation
SELECT *
FROM your_table
WHERE your_column ~ '^[a-zA-Z][a-zA-Z0-9_]{2,19}$';

How This Works

Query users table in PostgreSQL to find non-conforming usernames using regex operator for format validation. The regex pattern is used with PostgreSQL's ~ operator to filter rows at the database level.

Using regex directly in SQL is efficient for use cases like data validation — it avoids loading data into application memory just to filter it with a regex.

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