What is the usage of regular expressions in MySQL?

In MySQL, regular expressions are used in queries for searching a pattern in a string.

  • * Matches 0 more instances of the string preceding it.
  • + matches one more instances of the string preceding it.
  • ? Matches 0 or 1 instances of the string preceding it.
  • . Matches a single character.
  • [abc] matches a or b or z
  • | separates strings
  • ^ anchors the match from the start.
  • “.” Can be used to match any single character. “|” can be used to match either of the two strings
  • REGEXP can be used to match the input characters with the database.

Example:

The following statement retrieves all rows where column employee_name contains the text 1000 (example salary):

Select employee_name
From employee
Where employee_name REGEXP ‘1000
Order by employee_name