Detecting invalid values with regular expressions
In the video exercise, we saw that there are a number of ways to detect invalid values in our data. In this exercise, we will use regular expressions to identify records with invalid values in the parking_violation table.
A couple of regular expression patterns that will be useful in this exercise are c{n} and c+. c{n} matches strings which contain the character c repeated n times. For example, x{4} would match the pattern xxxx. c+ matches strings which contain the character c repeated one or more times. This pattern would match strings including xxxx as well as x and xx.
This exercise is part of the course
Cleaning Data in PostgreSQL Databases
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
SELECT
summons_number,
plate_id,
registration_state
FROM
parking_violation
WHERE
-- Define the pattern to use for matching
___ ___ ___ ___ ___;