ASA Getting Started
  Selecting Data from Database Tables
    Selecting rows from a table

Pattern matching in search conditions

Pattern matching is a versatile way of identifying character data. In SQL, the LIKE keyword is used to search for patterns. Pattern matching employs wildcard characters to match different combinations of characters.

List all employees whose last name begins with BR

• In Interactive SQL, type the following in the SQL Statements pane:

  SELECT emp_lname, emp_fname
  FROM employee
  WHERE emp_lname LIKE 'br%'

  emp_lname	emp_fname
  Breault	Robert
  Braun	Jane

  The % in the search condition indicates that any number of other characters may follow the letters BR.

List all employees whose last name begins with BR, followed by zero or more letters and a T, followed by zero or more letters

• In Interactive SQL, type the following in the SQL Statements pane:

  SELECT emp_lname, emp_fname
  FROM employee
  WHERE emp_lname LIKE 'BR%T%'

  emp_lname	emp_fname
  Breault	Robert

  The first % sign matches the string eaul, while the second % sign matches the empty string (no characters).

Another special character that can be used with LIKE is the _ (underscore) character, which matches exactly one character. For example, the pattern 'BR_U%' matches all names starting with BR and having U as the fourth letter. In Braun the _ character matches the letter A and the % matches N.

For more information, see LIKE conditions.