MySQL WHERE Clause
WHERE clause can be used within an SQL statement to narrow the result set down to a given set of criteria.
For example, you can narrow down the results of a
SELECT statement like this:
The above statement selects all records from the
actor table in the
sakila database where the value of the
first_name column is equal to
nick (not case-sensitive).
WHERE clause, the statement would return all records in the table. Depending on the database, this could potentially be thousands or even millions of records. If we were only interested in finding actors with a first name of "Nick" we would have a big job ahead of us.
WHERE clause is also used with the SQL
UPDATE statement to specify the record that is to be updated:
WHERE clause, all records would be updated.
The examples on this page use the Sakila sample database.