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6.3.4 UPDATE Command

The SQL UPDATE command is used to modify one or more rows in an existing table.

Syntax: 

UPDATE <table-name>
      SET <field-name> = <literal>
      [,<field-name> = <literal> [, ...]]
      [WHERE <condition>]
This command allows you to update columns of rows selected according to the conditions established with the WHERE condition. The format used for the WHERE condition is the same specified for the SELECT statement. If the WHERE clause is not specified, all the rows of the table are updated.

If the WHERE clause is specified and there are no rows matching the conditions specified, no row is updated. In this case no error is returned.

Note: You cannot change columns belonging to the primary key.