2.9. Deletions

Rows can be removed from a table using theDELETE command. Suppose you are no longer interested in the weather of Hayward. Then you can do the following to delete those rows from the table:

DELETE FROM weather WHERE city = 'Hayward';

All weather records belonging to Hayward are removed.

SELECT * FROM weather;

     city      | temp_lo | temp_hi | prcp |    date---------------+---------+---------+------+------------ San Francisco |      46 |      50 | 0.25 | 1994-11-27 San Francisco |      41 |      55 |    0 | 1994-11-29(2 rows)

One should be wary of statements of the form

DELETE FROMtablename;

Without a qualification,DELETE will removeall rows from the given table, leaving it empty. The system will not request confirmation before doing this!