Data in existing table rows can be changed with the UPDATE statement. This statement has the general form:UPDATE table SET column = value [WHERE search-condition];
The search condition specifies which rows in the table are to be updated. If no search condition is specified, all rows will be updated.
Update the exchange rate for US dollars to 7.25:UPDATE EXCHANGE_RATE SET RATE = 7.25 WHERE CURRENCY = 'USD';
Add 20 to the 1997-08-08 to 1997-11-14 price of a no-smoking, single room with shower in the Hotel Laponia:UPDATE ROOM_PRICES SET PRICE = PRICE + 20 WHERE ROOMTYPE = 'NSSGLS' AND FROM_DATE = DATE '1997-08-08' AND TO_DATE = DATE '1997-11-14' AND HOTELCODE = (SELECT HOTELCODE FROM HOTEL WHERE NAME = 'LAPONIA');
When a subselect is used in the search condition, the table being updated may not be used in the subselect.
Primary key columns can be updated provided the table is stored in a databank with the TRANS or LOG option.
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