In Oracle, UPDATE statement is used to update the existing records in a table. You can update a table in 2 ways.
Traditional Update table method
Syntax:
UPDATE table
SET column1 = expression1,
column2 = expression2,
...
column_n = expression_n
WHERE conditions;
Update Table by selecting rocords from another table
UPDATE table1
SET column1 = (SELECT expression1
FROM table2
WHERE conditions)
WHERE conditions;
Parameters:
1) column1, column2, … column_n:
It specifies the columns that you want to update.
2) expression1, expression2, …expression_n:
This specifies the values to assign to the column1, column2, ?. column_n.
3) conditions:It specifies the conditions that must be fulfilled for execution of UPDATE stateme.
Oracle Update Example: (Update single column)
UPDATE suppliers
SET supplier_name = 'Kingfisher'
WHERE supplier_id = 2;
This example will update the supplier_name as “Kingfisher” where “supplier_id” is 2.
Oracle Update Example: (Update multiple columns)
The following example specifies how to update multiple columns in a table. In this example, two columns supplier_name and supplier_address is updated by a single statement.
UPDATE suppliers
SET supplier_address = 'Agra',
supplier_name = 'Bata shoes'
WHERE supplier_id = 1;
Output:
1 row(s) updated.
0.06 seconds
Oracle Update Example: (By selecting records from another table)
UPDATE customers
SET name = (SELECT supplier_name
FROM suppliers
WHERE suppliers.supplier_name = customers.name)
WHERE age < 25;
Output:
2 row(s) updated.
0.02 seconds
Here, the customers table is updated by fetching the data from “suppliers” table.
Leave a Reply